Establishing a session or cellular Internet of Things packet transmission

ABSTRACT

An access and mobility management function (AMF) receives, from a wireless device, a request to establish a session. A control plane cellular internet of things (CIoT) indication requesting discovery of a session management function (SMF) that supports exchange of user data between the wireless device and the SMF using a non-access stratum message is sent to a network repository function (NRF). An identifier of the SMF is received from the NRF. A request to establish the session for CIoT packet transmission is sent to the SMF.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent Ser. No. 16/366,688, filed on Mar. 27, 2019, which claims the benefit of U.S. Provisional Application No. 62/654,882, filed Apr. 9, 2018, which is hereby incorporated by reference in its entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present invention are described herein with reference to the drawings.

FIG. 1 is a diagram of an example 5G system architecture as per an aspect of an embodiment of the present disclosure.

FIG. 2 is a diagram of an example 5G System architecture as per an aspect of an embodiment of the present disclosure.

FIG. 3 is a system diagram of an example wireless device and a network node in a 5G system as per an aspect of an embodiment of the present disclosure.

FIG. 4 is a system diagram of an example wireless device as per an aspect of an embodiment of the present disclosure.

FIG. 5A and FIG. 5B depict two registration management state models in UE 100 and AMF 155 as per an aspect of embodiments of the present disclosure.

FIG. 6A and FIG. 6B depict two connection management state models in UE 100 and AMF 155 as per an aspect of embodiments of the present disclosure.

FIG. 7 is diagram for classification and marking traffic as per an aspect of an embodiment of the present disclosure.

FIG. 8 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 9 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 10 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 11 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 12 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 13 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 14 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 15 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 16 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 17 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 18 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 19 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 20 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 21 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 22 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 23 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 24 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 25 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 26 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 27 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 28 is an example call flow as per an aspect of an embodiment of the present disclosure.

FIG. 29 is an example flow diagram as per an aspect of an embodiment of the present disclosure.

FIG. 30 is an example flow diagram as per an aspect of an embodiment of the present disclosure.

FIG. 31 is an example flow diagram as per an aspect of an embodiment of the present disclosure.

FIG. 32 is an example flow diagram as per an aspect of an embodiment of the present disclosure.

FIG. 33 is an example flow diagram as per an aspect of an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present invention enable implementation of enhanced features and functionalities in 5G systems. Embodiments of the technology disclosed herein may be employed in the technical field of 5G systems, 5G Cellular Internet of Things (IoT), Machine Type Communication (MTC), and network slicing for communication systems. More particularly, the embodiments of the technology disclosed herein may relate to 5G core network and 5G systems for 5G Cellular Internet of Things (IoT), Machine Type Communication (MTC), and network slicing in communication systems. Throughout the present disclosure, UE, wireless device, and mobile device are used interchangeably. Throughout the present disclosure, CIoT, and MTC are used interchangeably.

The following acronyms are used throughout the present disclosure:

5G 5th generation mobile networks

5GC 5G Core Network

5GS 5G System

5G-AN 5G Access Network

5QI 5G QoS Indicator

AF Application Function

AMF Access and Mobility Management Function

AN Access Network

AS Application Server

CDR Charging Data Record

CCNF Common Control Network Functions

CIoT Cellular IoT

CN Core Network

CP Control Plane

DDN Downlink Data Notification

DL Downlink

DN Data Network

DNN Data Network Name

F-TEID Fully Qualified TEID

FQDN Fully Qualified Domain Name

GPSI Generic Public Subscription Identifier

GTP GPRS Tunneling Protocol

GUTI Globally Unique Temporary Identifier

IMSI International Mobile Subscriber Identity

IoT Internet of Things

LADN Local Area Data Network

LI Lawful Intercept

MEI Mobile Equipment Identifier

MICO Mobile Initiated Connection Only

MME Mobility Management Entity

MO Mobile Originated

MSISDN Mobile Subscriber ISDN

MT Mobile Terminating

MTC Machine Type Communication

N3IWF Non-3GPP InterWorking Function

NAI Network Access Identifier

NAS Non-Access Stratum

NB-IoT Narrow Band IoT

NEF Network Exposure Function

NF Network Function

NGAP Next Generation Application Protocol

NIMF Network IoT Messaging Function

NR New Radio

NRF Network Repository Function

NSI Network Slice Instance

NSSAI Network Slice Selection Assistance Information

NSSF Network Slice Selection Function

OCS Online Charging System

OFCS Offline Charging System

PCF Policy Control Function

PDU Packet/Protocol Data Unit

PEI Permanent Equipment Identifier

PLMN Public Land Mobile Network

RAN Radio Access Network

QFI QoS Flow Identity

RM Registration Management

S1-AP S1 Application Protocol

SBA Service Based Architecture

SEA Security Anchor Function

SCM Security Context Management

SCS Service Capability Server

SMF Session Management Function

SMSF SMS Function

S-NSSAI Single Network Slice Selection Assistance information

SUCI Served User Correlation ID

SUPI Subscriber Permanent Identifier

TEID Tunnel Endpoint Identifier

UE User Equipment

UL Uplink

UL CL Uplink Classifier

UPF User Plane Function

URRP UE Reachability Request Parameter

Example FIG. 1 and FIG. 2 depict a 5G system comprising of access networks and 5G core network. An example 5G access network may comprise an access network connecting to a 5G core network. An access network may comprise an NG-RAN 105 and/or non-3GPP AN 165. An example 5G core network may connect to one or more 5G access networks 5G-AN and/or NG-RANs. 5G core network may comprise functional elements or network functions as in example FIG. 1 and example FIG. 2 where interfaces may be employed for communication among the functional elements and/or network elements.

In an example, a network function may be a processing function in a network, which may have a functional behavior and/or interfaces. A network function may be implemented either as a network element on a dedicated hardware, and/or a network node as depicted in FIG. 3 and FIG. 4 , or as a software instance running on a dedicated hardware and/or shared hardware, or as a virtualized function instantiated on an appropriate platform.

In an example, access and mobility management function, AMF 155, may include the following functionalities (some of the AMF 155 functionalities may be supported in a single instance of an AMF 155): termination of RAN 105 CP interface (N2), termination of NAS (N1), NAS ciphering and integrity protection, registration management, connection management, reachability management, mobility management, lawful intercept (for AMF 155 events and interface to LI system), provide transport for session management, SM messages between UE 100 and SMF 160, transparent proxy for routing SM messages, access authentication, access authorization, provide transport for SMS messages between UE 100 and SMSF, security anchor function, SEA, interaction with the AUSF 150 and the UE 100, receiving the intermediate key established as a result of the UE 100 authentication process, security context management, SCM, that receives a key from the SEA that it uses to derive access network specific keys, and/or the like.

In an example, the AMF 155 may support non-3GPP access networks through N2 interface with N3IWF 170, NAS signaling with a UE 100 over N3IWF 170, authentication of UEs connected over N3IWF 170, management of mobility, authentication, and separate security context state(s) of a UE 100 connected via non-3GPP access 165 or connected via 3GPP access 105 and non-3GPP access 165 simultaneously, support of a coordinated RM context valid over 3GPP access 105 and non 3GPP access 165, support of CM management contexts for the UE 100 for connectivity over non-3GPP access, and/or the like.

In an example, an AMF 155 region may comprise one or multiple AMF 155 sets. The AMF 155 set may comprise some AMF 155 that serve a given area and/or network slice(s). In an example, multiple AMF 155 sets may be per AMF 155 region and/or network slice(s). Application identifier may be an identifier that may be mapped to a specific application traffic detection rule. Configured NSSAI may be an NSSAI that may be provisioned in a UE 100. DN 115 access identifier (DNAI), for a DNN, may be an identifier of a user plane access to a DN 115. Initial registration may be related to a UE 100 registration in RM-DEREGISTERED 500, 520 states. N2AP UE 100 association may be a logical per UE 100 association between a 5G AN node and an AMF 155. N2AP UE-TNLA-binding may be a binding between a N2AP UE 100 association and a specific transport network layer, TNL association for a given UE 100.

In an example, session management function, SMF 160, may include one or more of the following functionalities (one or more of the SMF 160 functionalities may be supported in a single instance of a SMF 160): session management (e.g. session establishment, modify and release, including tunnel maintain between UPF 110 and AN 105 node), UE 100 IP address allocation & management (including optional authorization), selection and control of UP function(s), configuration of traffic steering at UPF 110 to route traffic to proper destination, termination of interfaces towards policy control functions, control part of policy enforcement and QoS, lawful intercept (for SM events and interface to LI System), termination of SM parts of NAS messages, downlink data notification, initiation of AN specific SM information, sent via AMF 155 over N2 to (R)AN 105, determination of SSC mode of a session, roaming functionality, handling local enforcement to apply QoS SLAs (VPLMN), charging data collection and charging interface (VPLMN), lawful intercept (in VPLMN for SM events and interface to LI System), support for interaction with external DN 115 for transport of signaling for PDU session authorization/authentication by external DN 115, and/or the like.

In an example, a user plane function, UPF 110, may include one or more of the following functionalities (some of the UPF 110 functionalities may be supported in a single instance of a UPF 110): anchor point for Intra-/Inter-RAT mobility (when applicable), external PDU session point of interconnect to DN 115, packet routing & forwarding, packet inspection and user plane part of policy rule enforcement, lawful intercept (UP collection), traffic usage reporting, uplink classifier to support routing traffic flows to a data network, branching point to support multi-homed PDU session(s), QoS handling for user plane, uplink traffic verification (SDF to QoS flow mapping), transport level packet marking in the uplink and downlink, downlink packet buffering, downlink data notification triggering, and/or the like.

In an example, the UE 100 IP address management may include allocation and release of the UE 100 IP address and/or renewal of the allocated IP address. The UE 100 may set a requested PDU type during a PDU session establishment procedure based on its IP stack capabilities and/or configuration. In an example, the SMF 160 may select PDU type of a PDU session. In an example, if the SMF 160 receives a request with PDU type set to IP, the SMF 160 may select PDU type IPv4 or IPv6 based on DNN configuration and/or operator policies. In an example, the SMF 160 may provide a cause value to the UE 100 to indicate whether the other IP version is supported on the DNN. In an example, if the SMF 160 receives a request for PDU type IPv4 or IPv6 and the requested IP version is supported by the DNN the SMF 160 may select the requested PDU type.

In an example embodiment, the 5GC elements and UE 100 may support the following mechanisms: during a PDU session establishment procedure, the SMF 160 may send the IP address to the UE 100 via SM NAS signaling. The IPv4 address allocation and/or IPv4 parameter configuration via DHCPv4 may be employed once PDU session may be established. IPv6 prefix allocation may be supported via IPv6 stateless autoconfiguration, if IPv6 is supported. In an example, 5GC network elements may support IPv6 parameter configuration via stateless DHCPv6.

The 5GC may support the allocation of a static IPv4 address and/or a static IPv6 prefix based on subscription information in a UDM 140 and/or based on the configuration on a per-subscriber, per-DNN basis.

User plane function(s) (UPF 110) may handle the user plane path of PDU sessions. A UPF 110 that provides the interface to a data network may support functionality of a PDU session anchor.

In an example, a policy control function, PCF 135, may support unified policy framework to govern network behavior, provide policy rules to control plane function(s) to enforce policy rules, implement a front end to access subscription information relevant for policy decisions in a user data repository (UDR), and/or the like.

A network exposure function, NEF 125, may provide means to securely expose the services and capabilities provided by the 3GPP network functions, translate between information exchanged with the AF 145 and information exchanged with the internal network functions, receive information from other network functions, and/or the like.

In an example, an network repository function, NRF 130 may support service discovery function that may receive NF discovery request from NF instance, provide information about the discovered NF instances (be discovered) to the NF instance, and maintain information about available NF instances and their supported services, and/or the like.

In an example, an NSSF 120 may select a set of network slice instances serving the UE 100, may determine allowed NSSAI. In an example, the NSSF 120 may determine the AMF 155 set to be employed to serve the UE 100, and/or, based on configuration, determine a list of candidate AMF 155(s) 155 by querying the NRF 130.

In an example, stored data in a UDR may include at least user subscription data, including at least subscription identifiers, security credentials, access and mobility related subscription data, session related subscription data, policy data, and/or the like.

In an example, an AUSF 150 may support authentication server function (AUSF 150).

In an example, an application function, AF 145, may interact with the 3GPP core network to provide services. In an example, based on operator deployment, application functions may be trusted by the operator to interact directly with relevant network functions. Application functions not allowed by the operator to access directly the network functions may use an external exposure framework (e.g., via the NEF) to interact with relevant network functions.

In an example, control plane interface between the (R)AN 105 and the 5G core may support connection of multiple different kinds of AN(s) (e.g. 3GPP RAN 105, N3IWF 170 for Un-trusted access 165) to the 5GC via a control plane protocol. In an example, an N2 AP protocol may be employed for both the 3GPP access 105 and non-3GPP access 165. In an example, control plane interface between the (R)AN 105 and the 5G core may support decoupling between AMF 155 and other functions such as SMF 160 that may need to control the services supported by AN(s) (e.g. control of the UP resources in the AN 105 for a PDU session).

In an example, the 5GC may provide policy information from the PCF 135 to the UE 100. In an example, the policy information may comprise: access network discovery and selection policy, UE 100 route selection policy (URSP), SSC mode selection policy (SSCMSP), network slice selection policy (NSSP), DNN selection policy, non-seamless offload policy, and/or the like.

In an example, as depicted in example FIG. 5A and FIG. 5B, the registration management, RM may be employed to register or de-register a UE/user 100 with the network, and establish the user context in the network. Connection management may be employed to establish and release the signaling connection between the UE 100 and the AMF 155.

In an example, a UE 100 may register with the network to receive services that require registration. In an example, the UE 100 may update its registration with the network periodically in order to remain reachable (periodic registration update), or upon mobility (e.g., mobility registration update), or to update its capabilities or to re-negotiate protocol parameters.

In an example, an initial registration procedure as depicted in example FIG. 8 and FIG. 9 may involve execution of network access control functions (e.g. user authentication and access authorization based on subscription profiles in UDM 140). Example FIG. 9 is a continuation of the initial registration procedure depicted in FIG. 8 . As a result of the initial registration procedure, the identity of the serving AMF 155 may be registered in a UDM 140.

In an example, the registration management, RM procedures may be applicable over both 3GPP access 105 and non 3GPP access 165.

An example FIG. 5A may depict the RM states of a UE 100 as observed by the UE 100 and AMF 155. In an example embodiment, two RM states may be employed in the UE 100 and the AMF 155 that may reflect the registration status of the UE 100 in the selected PLMN: RM-DEREGISTERED 500, and RM-REGISTERED 510. In an example, in the RM DEREGISTERED state 500, the UE 100 may not be registered with the network. The UE 100 context in the AMF 155 may not hold valid location or routing information for the UE 100 so the UE 100 may not be reachable by the AMF 155. In an example, the UE 100 context may be stored in the UE 100 and the AMF 155. In an example, in the RM REGISTERED state 510, the UE 100 may be registered with the network. In the RM-REGISTERED 510 state, the UE 100 may receive services that may require registration with the network.

In an example embodiment, two RM states may be employed in AMF 155 for the UE 100 that may reflect the registration status of the UE 100 in the selected PLMN: RM-DEREGISTERED 520, and RM-REGISTERED 530.

As depicted in example FIG. 6A and FIG. 6B, connection management, CM, may comprise establishing and releasing a signaling connection between a UE 100 and an AMF 155 over N1 interface. The signaling connection may be employed to enable NAS signaling exchange between the UE 100 and the core network. The signaling connection between the UE 100 and the AMF 155 may comprise both the AN signaling connection between the UE 100 and the (R)AN 105 (e.g. RRC connection over 3GPP access) and the N2 connection for the UE 100 between the AN and the AMF 155.

As depicted in example FIG. 6A and FIG. 6B, two CM states may be employed for the NAS signaling connectivity of the UE 100 with the AMF 155, CM-IDLE 600, 620 and CM-CONNECTED 610, 630. A UE 100 in CM-IDLE 600 state may be in RM-REGISTERED 510 state and may have no NAS signaling connection established with the AMF 155 over N1. The UE 100 may perform cell selection, cell reselection, PLMN selection, and/or the like. A UE 100 in CM-CONNECTED 610 state may have a NAS signaling connection with the AMF 155 over N1.

In an example embodiment two CM states may be employed for the UE 100 at the AMF 155, CM-IDLE 620 and CM-CONNECTED 630.

In an example, an RRC inactive state may apply to NG-RAN (e.g. it may apply to NR and E-UTRA connected to 5G CN). The AMF 155, based on network configuration, may provide assistance information to the NG RAN 105, to assist the NG RAN's 105 decision whether the UE 100 may be sent to RRC inactive state. When a UE 100 is CM-CONNECTED 610 with RRC inactive state, the UE 100 may resume the RRC connection due to uplink data pending, mobile initiated signaling procedure, as a response to RAN 105 paging, to notify the network that it has left the RAN 105 notification area, and/or the like.

In an example, a NAS signaling connection management may include establishing and releasing a NAS signaling connection. A NAS signaling connection establishment function may be provided by the UE 100 and the AMF 155 to establish the NAS signaling connection for the UE 100 in CM-IDLE 600 state. The procedure of releasing the NAS signaling connection may be initiated by the 5G (R)AN 105 node or the AMF 155.

In an example, reachability management of a UE 100 may detect whether the UE 100 is reachable and may provide the UE 100 location (e.g. access node) to the network to reach the UE 100. Reachability management may be done by paging the UE 100 and the UE 100 location tracking. The UE 100 location tracking may include both UE 100 registration area tracking and UE 100 reachability tracking. The UE 100 and the AMF 155 may negotiate UE 100 reachability characteristics in CM-IDLE 600, 620 state during registration and registration update procedures.

In an example, two UE 100 reachability categories may be negotiated between a UE 100 and an AMF 155 for CM-IDLE 600, 620 state. 1) UE 100 reachability allowing mobile device terminated data while the UE 100 is CM-IDLE 600 mode. 2) Mobile initiated connection only (MICO) mode. The 5GC may support a PDU connectivity service that provides exchange of PDUs between the UE 100 and a data network identified by a DNN. The PDU connectivity service may be supported via PDU sessions that are established upon request from the UE 100.

In an example, a PDU session may support one or more PDU session types. PDU sessions may be established (e.g. upon UE 100 request), modified (e.g. upon UE 100 and 5GC request) and/or released (e.g. upon UE 100 and 5GC request) using NAS SM signaling exchanged over N1 between the UE 100 and the SMF 160. Upon request from an application server, the 5GC may be able to trigger a specific application in the UE 100. When receiving the trigger, the UE 100 may send it to the identified application in the UE 100. The identified application in the UE 100 may establish a PDU session to a specific DNN.

In an example, the 5G QoS model may support a QoS flow based framework as depicted in example FIG. 7 . The 5G QoS model may support both QoS flows that require a guaranteed flow bit rate and QoS flows that may not require a guaranteed flow bit rate. In an example, the 5G QoS model may support reflective QoS. The QoS model may comprise flow mapping or packet marking at the UPF 110 (CN_UP) 110, AN 105 and/or the UE 100. In an example, packets may arrive from and/or destined to the application/service layer 730 of UE 100, UPF 110 (CN_UP) 110, and/or the AF 145.

In an example, the QoS flow may be a granularity of QoS differentiation in a PDU session. A QoS flow ID, QFI, may be employed to identify the QoS flow in the 5G system. In an example, user plane traffic with the same QFI within a PDU session may receive the same traffic forwarding treatment. The QFI may be carried in an encapsulation header on N3 and/or N9 (e.g. without any changes to the end-to-end packet header). In an example, the QFI may be applied to PDUs with different types of payload. The QFI may be unique within a PDU session.

In an example, the QoS parameters of a QoS flow may be provided to the (R)AN 105 as a QoS profile over N2 at PDU session establishment, QoS flow establishment, or when NG-RAN is used at every time the user plane is activated. In an example, a default QoS rule may be required for every PDU session. The SMF 160 may allocate the QFI for a QoS flow and may derive QoS parameters from the information provided by the PCF 135. In an example, the SMF 160 may provide the QFI together with the QoS profile containing the QoS parameters of a QoS flow to the (R)AN 105.

In an example, 5G QoS flow may be a granularity for QoS forwarding treatment in the 5G system. Traffic mapped to the same 5G QoS flow may receive the same forwarding treatment (e.g. scheduling policy, queue management policy, rate shaping policy, RLC configuration, and/or the like). In an example, providing different QoS forwarding treatment may require separate 5G QoS flows.

In an example, a 5G QoS indicator may be a scalar that may be employed as a reference to a specific QoS forwarding behavior (e.g. packet loss rate, packet delay budget) to be provided to a 5G QoS flow. In an example, the 5G QoS indicator may be implemented in the access network by the 5QI referencing node specific parameters that may control the QoS forwarding treatment (e.g. scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, and/or the like.).

In an example, 5GC may support edge computing and may enable operator(s) and 3rd party services to be hosted close to the UE's access point of attachment. The 5G core network may select a UPF 110 close to the UE 100 and may execute the traffic steering from the UPF 110 to the local data network via a N6 interface. In an example, the selection and traffic steering may be based on the UE's 100 subscription data, UE 100 location, the information from application function AF 145, policy, other related traffic rules, and/or the like. In an example, the 5G core network may expose network information and capabilities to an edge computing application function. The functionality support for edge computing may include local routing where the 5G core network may select a UPF 110 to route the user traffic to the local data network, traffic steering where the 5G core network may select the traffic to be routed to the applications in the local data network, session and service continuity to enable UE 100 and application mobility, user plane selection and reselection, e.g. based on input from application function, network capability exposure where 5G core network and application function may provide information to each other via NEf 125, QoS and charging where PCF 135 may provide rules for QoS control and charging for the traffic routed to the local data network, support of local area data network where 5G core network may provide support to connect to the LADN in a certain area where the applications are deployed, and/or the like.

An example 5G system may be a 3GPP system comprising of 5G access network 105, 5G core network and a UE 100, and/or the like. Allowed NSSAI may be an NSSAI provided by a serving PLMN during e.g. a registration procedure, indicating the NSSAI allowed by the network for the UE 100 in the serving PLMN for the current registration area.

In an example, a PDU connectivity service may provide exchange of PDUs between a UE 100 and a data network. A PDU session may be an association between the UE 100 and the data network, DN 115, that may provide the PDU connectivity service. The type of association may be IP, Ethernet and/or unstructured.

Establishment of user plane connectivity to a data network via network slice instance(s) may comprise the following: performing a RM procedure to select an AMF 155 that supports the required network slices, and establishing one or more PDU session(s) to the required data network via the network slice instance(s).

In an example, the set of network slices for a UE 100 may be changed at any time while the UE 100 may be registered with the network, and may be initiated by the network, or the UE 100.

In an example, a periodic registration update may be UE 100 re-registration at expiry of a periodic registration timer. A requested NSSAI may be a NSSAI that the UE 100 may provide to the network.

In an example, a service based interface may represent how a set of services may be provided/exposed by a given NF.

In an example, a service continuity may be an uninterrupted user experience of a service, including the cases where the IP address and/or anchoring point may change. In an example, a session continuity may refer to continuity of a PDU session. For PDU session of IP type session continuity may imply that the IP address is preserved for the lifetime of the PDU session. An uplink classifier may be a UPF 110 functionality that aims at diverting uplink traffic, based on filter rules provided by the SMF 160, towards data network, DN 115.

In an example, the 5G system architecture may support data connectivity and services enabling deployments to use techniques such as e.g. network function virtualization and/or software defined networking. The 5G system architecture may leverage service-based interactions between control plane (CP) network functions where identified. In 5G system architecture, separation of the user plane (UP) functions from the control plane functions may be considered. A 5G system may enable a network function to interact with other NF(s) directly if required.

In an example, the 5G system may reduce dependencies between the access network (AN) and the core network (CN). The architecture may comprise a converged access-agnostic core network with a common AN-CN interface which may integrate different 3GPP and non-3GPP access types.

In an example, the 5G system may support a unified authentication framework, stateless NFs, where the compute resource is decoupled from the storage resource, capability exposure, and concurrent access to local and centralized services. To support low latency services and access to local data networks, UP functions may be deployed close to the access network.

In an example, the 5G system may support roaming with home routed traffic and/or local breakout traffic in the visited PLMN. An example 5G architecture may be service-based and the interaction between network functions may be represented in two ways. (1) As service-based representation (depicted in example FIG. 1 ), where network functions within the control plane, may enable other authorized network functions to access their services. This representation may also include point-to-point reference points where necessary. (2) Reference point representation, showing the interaction between the NF services in the network functions described by point-to-point reference point (e.g. N11) between any two network functions.

In an example, a network slice may comprise the core network control plane and user plane network functions, the 5G Radio Access Network; the N3IWF functions to the non-3GPP Access Network, and/or the like. Network slices may differ for supported features and network function implementation. The operator may deploy multiple network slice instances delivering the same features but for different groups of UEs, e.g. as they deliver a different committed service and/or because they may be dedicated to a customer. The NSSF 120 may store the mapping information between slice instance ID and NF ID (or NF address).

In an example, a UE 100 may simultaneously be served by one or more network slice instances via a 5G-AN. In an example, the UE 100 may be served by k network slices (e.g. k=8, 16, etc.) at a time. An AMF 155 instance serving the UE 100 logically may belong to a network slice instance serving the UE 100.

In an example, a PDU session may belong to one specific network slice instance per PLMN. In an example, different network slice instances may not share a PDU session. Different slices may have slice-specific PDU sessions using the same DNN.

An S-NSSAI (Single Network Slice Selection Assistance information) may identify a network slice. An S-NSSAI may comprise a slice/service type (SST), which may refer to the expected network slice behavior in terms of features and services; and/or a slice differentiator (SD). A slice differentiator may be optional information that may complement the slice/service type(s) to allow further differentiation for selecting a network slice instance from potentially multiple network slice instances that comply with the indicated slice/service type. In an example, the same network slice instance may be selected employing different S-NSSAIs. The CN part of a network slice instance(s) serving a UE 100 may be selected by CN.

In an example, subscription data may include the S-NSSAI(s) of the network slices that the UE 100 subscribes to. One or more S-NSSAIs may be marked as default S-NSSAI. In an example, k S-NSSAI may be marked default S-NSSAI (e.g. k=8, 16, etc.). In an example, the UE 100 may subscribe to more than 8 S-NSSAIs.

In an example, a UE 100 may be configured by the HPLMN with a configured NSSAI per PLMN. Upon successful completion of a UE's registration procedure, the UE 100 may obtain from the AMF 155 an Allowed NSSAI for this PLMN, which may include one or more S-NSSAIs.

In an example, the Allowed NSSAI may take precedence over the configured NSSAI for a PLMN. The UE 100 may use the S-NSSAIs in the allowed NSSAI corresponding to a network slice for the subsequent network slice selection related procedures in the serving PLMN.

In an example, the establishment of user plane connectivity to a data network via a network slice instance(s) may comprise: performing a RM procedure to select an AMF 155 that may support the required network slices, establishing one or more PDU sessions to the required data network via the network slice instance(s), and/or the like.

In an example, when a UE 100 registers with a PLMN, if the UE 100 for the PLMN has a configured NSSAI or an allowed NSSAI, the UE 100 may provide to the network in RRC and NAS layer a requested NSSAI comprising the S-NSSAI(s) corresponding to the slice(s) to which the UE 100 attempts to register, a temporary user ID if one was assigned to the UE, and/or the like. The requested NSSAI may be configured-NSSAI, allowed-NSSAI, and/or the like.

In an example, when a UE 100 registers with a PLMN, if for the PLMN the UE 100 has no configured NSSAI or allowed NSSAI, the RAN 105 may route NAS signaling from/to the UE 100 to/from a default AMF 155.

In an example, the network, based on local policies, subscription changes and/or UE 100 mobility, may change the set of permitted network slice(s) to which the UE 100 is registered. In an example, the network may perform the change during a registration procedure or trigger a notification towards the UE 100 of the change of the supported network slices using an RM procedure (which may trigger a registration procedure). The network may provide the UE 100 with a new allowed NSSAI and tracking area list.

In an example, during a registration procedure in a PLMN, in case the network decides that the UE 100 should be served by a different AMF 155 based on network slice(s) aspects, the AMF 155 that first received the registration request may redirect the registration request to another AMF 155 via the RAN 105 or via direct signaling between the initial AMF 155 and the target AMF 155.

In an example, the network operator may provision the UE 100 with network slice selection policy (NSSP). The NSSP may comprise one or more NSSP rules.

In an example, if a UE 100 has one or more PDU sessions established corresponding to a specific S-NSSAI, the UE 100 may route the user data of the application in one of the PDU sessions, unless other conditions in the UE 100 may prohibit the use of the PDU sessions. If the application provides a DNN, then the UE 100 may consider the DNN to determine which PDU session to use. In an example, if the UE 100 does not have a PDU session established with the specific S-NSSAI, the UE 100 may request a new PDU session corresponding to the S-NSSAI and with the DNN that may be provided by the application. In an example, in order for the RAN 105 to select a proper resource for supporting network slicing in the RAN 105, the RAN 105 may be aware of the network slices used by the UE 100.

In an example, an AMF 155 may select an SMF 160 in a network slice instance based on S-NSSAI, DNN and/or other information e.g. UE 100 subscription and local operator policies, and/or the like, when the UE 100 triggers the establishment of a PDU session. The selected SMF 160 may establish the PDU session based on S-NSSAI and DNN.

In an example, in order to support network-controlled privacy of slice information for the slices the UE 100 may access, when the UE 100 is aware or configured that privacy considerations may apply to NSSAI, the UE 100 may not include NSSAI in NAS signaling unless the UE 100 has a NAS security context and the UE 100 may not include NSSAI in unprotected RRC signaling.

In an example, for roaming scenarios, the network slice specific network functions in VPLMN and HPLMN may be selected based on the S-NSSAI provided by the UE 100 during PDU connection establishment. If a standardized S-NSSAI is used, selection of slice specific NF instances may be done by each PLMN based on the provided S-NSSAI. In an example, the VPLMN may map the S-NSSAI of HPLMN to a S-NSSAI of VPLMN based on roaming agreement (e.g., including mapping to a default S-NSSAI of VPLMN). In an example, the selection of slice specific NF instance in VPLMN may be done based on the S-NSSAI of VPLMN. In an example, the selection of any slice specific NF instance in HPLMN may be based on the S-NSSAI of HPLMN.

As depicted in example FIG. 8 and FIG. 9 , a registration procedure may be performed by the UE 100 to get authorized to receive services, to enable mobility tracking, to enable reachability, and/or the like.

In an example, the UE 100 may send to the (R)AN 105 an AN message (comprising AN parameters, RM-NAS registration request (registration type, SUCI or SUPI or 5G-GUTI, last visited TAI (if available), security parameters, requested NSSAI, mapping of requested NSSAI, UE 100 5GC capability, PDU session status, PDU session(s) to be re-activated, Follow on request, MICO mode preference, and/or the like), and/or the like). In an example, in case of NG-RAN, the AN parameters may include e.g. SUCI or SUPI or the 5G-GUTI, the Selected PLMN ID and requested NSSAI, and/or the like. In an example, the AN parameters may comprise establishment cause. The establishment cause may provide the reason for requesting the establishment of an RRC connection. In an example, the registration type may indicate if the UE 100 wants to perform an initial registration (i.e. the UE 100 is in RM-DEREGISTERED state), a mobility registration update (e.g., the UE 100 is in RM-REGISTERED state and initiates a registration procedure due to mobility), a periodic registration update (e.g., the UE 100 is in RM-REGISTERED state and may initiate a registration procedure due to the periodic registration update timer expiry) or an emergency registration (e.g., the UE 100 is in limited service state). In an example, if the UE 100 performing an initial registration (i.e., the UE 100 is in RM-DEREGISTERED state) to a PLMN for which the UE 100 does not already have a 5G-GUTI, the UE 100 may include its SUCI or SUPI in the registration request. The SUCI may be included if the home network has provisioned the public key to protect SUPI in the UE. If the UE 100 received a UE 100 configuration update command indicating that the UE 100 needs to re-register and the 5G-GUTI is invalid, the UE 100 may perform an initial registration and may include the SUPI in the registration request message. For an emergency registration, the SUPI may be included if the UE 100 does not have a valid 5G-GUTI available; the PEI may be included when the UE 100 has no SUPI and no valid 5G-GUTI. In other cases, the 5G-GUTI may be included and it may indicate the last serving AMF 155. If the UE 100 is already registered via a non-3GPP access in a PLMN different from the new PLMN (e.g., not the registered PLMN or an equivalent PLMN of the registered PLMN) of the 3GPP access, the UE 100 may not provide over the 3GPP access the 5G-GUTI allocated by the AMF 155 during the registration procedure over the non-3GPP access. If the UE 100 is already registered via a 3GPP access in a PLMN (e.g., the registered PLMN), different from the new PLMN (i.e. not the registered PLMN or an equivalent PLMN of the registered PLMN) of the non-3GPP access, the UE 100 may not provide over the non-3GPP access the 5G-GUTI allocated by the AMF 155 during the registration procedure over the 3GPP access. The UE 100 may provide the UE's usage setting based on its configuration. In case of initial registration or mobility registration update, the UE 100 may include the mapping of requested NSSAI, which may be the mapping of each S-NSSAI of the requested NSSAI to the S-NSSAIs of the configured NSSAI for the HPLMN, to ensure that the network is able to verify whether the S-NSSAI(s) in the requested NSSAI are permitted based on the subscribed S-NSSAIs. If available, the last visited TAI may be included in order to help the AMF 155 produce registration area for the UE. In an example, the security parameters may be used for authentication and integrity protection. requested NSSAI may indicate the network slice selection assistance information. The PDU session status may indicates the previously established PDU sessions in the UE. When the UE 100 is connected to the two AMF 155 belonging to different PLMN via 3GPP access and non-3GPP access then the PDU session status may indicate the established PDU session of the current PLMN in the UE. The PDU session(s) to be re-activated may be included to indicate the PDU session(s) for which the UE 100 may intend to activate UP connections. A PDU session corresponding to a LADN may not be included in the PDU session(s) to be re-activated when the UE 100 is outside the area of availability of the LADN. The follow on request may be included when the UE 100 may have pending uplink signaling and the UE 100 may not include PDU session(s) to be re-activated, or the registration type may indicate the UE 100 may want to perform an emergency registration.

In an example, if a SUPI is included or the 5G-GUTI does not indicate a valid AMF 155, the (R)AN 105, based on (R)AT and requested NSSAI, if available, may selects an AMF 155. If UE 100 is in CM-CONNECTED state, the (R)AN 105 may forward the registration request message to the AMF 155 based on the N2 connection of the UE. If the (R)AN 105 may not select an appropriate AMF 155, it may forward the registration request to an AMF 155 which has been configured, in (R)AN 105, to perform AMF 155 selection.

In an example, the (R)AN 105 may send to the new AMF 155 an N2 message (comprising: N2 parameters, RM-NAS registration request (registration type, SUPI or 5G-GUTI, last visited TAI (if available), security parameters, requested NSSAI, mapping of requested NSSAI, UE 100 5GC capability, PDU session status, PDU session(s) to be re-activated, follow on request, and MICO mode preference), and/or the like). In an example, when NG-RAN is used, the N2 parameters may comprise the selected PLMN ID, location information, cell identity and the RAT type related to the cell in which the UE 100 is camping. In an example, when NG-RAN is used, the N2 parameters may include the establishment cause.

In an example, the new AMF 155 may send to the old AMF 155 an Namf_Communication_UEContextTransfer (complete registration request). In an example, if the UE's 5G-GUTI was included in the registration request and the serving AMF 155 has changed since last registration procedure, the new AMF 155 may invoke the Namf_Communication_UEContextTransfer service operation on the old AMF 155 including the complete registration request IE, which may be integrity protected, to request the UE's SUPI and MM Context. The old AMF 155 may use the integrity protected complete registration request IE to verify if the context transfer service operation invocation corresponds to the UE 100 requested. In an example, the old AMF 155 may transfer the event subscriptions information by each NF consumer, for the UE, to the new AMF 155. In an example, if the UE 100 identifies itself with PEI, the SUPI request may be skipped.

In an example, the old AMF 155 may send to new AMF 155 a response to Namf_Communication_UEContextTransfer (SUPI, MM context, SMF 160 information, PCF ID). In an example, the old AMF 155 may respond to the new AMF 155 for the Namf_Communication_UEContextTransfer invocation by including the UE's SUPI and MM context. In an example, if old AMF 155 holds information about established PDU sessions, the old AMF 155 may include SMF 160 information including S-NSSAI(s), SMF 160 identities and PDU session ID. In an example, if old AMF 155 holds information about active NGAP UE-TNLA bindings to N3IWF, the old AMF 155 may include information about the NGAP UE-TNLA bindings.

In an example, if the SUPI is not provided by the UE 100 nor retrieved from the old AMF 155 the identity request procedure may be initiated by the AMF 155 sending an identity request message to the UE 100 requesting the SUCI.

In an example, the UE 100 may respond with an identity response message including the SUCI. The UE 100 may derive the SUCI by using the provisioned public key of the HPLMN.

In an example, the AMF 155 may decide to initiate UE 100 authentication by invoking an AUSF 150. The AMF 155 may select an AUSF 150 based on SUPI or SUCI. In an example, if the AMF 155 is configured to support emergency registration for unauthenticated SUPIs and the UE 100 indicated registration type emergency registration the AMF 155 may skip the authentication and security setup or the AMF 155 may accept that the authentication may fail and may continue the registration procedure.

In an example, the authentication may be performed by Nudm_UEAuthenticate_Get operation. The AUSF 150 may discover a UDM 140. In case the AMF 155 provided a SUCI to AUSF 150, the AUSF 150 may return the SUPI to AMF 155 after the authentication is successful. In an example, if network slicing is used, the AMF 155 may decide if the registration request needs to be rerouted where the initial AMF 155 refers to the AMF 155. In an example, the AMF 155 may initiate NAS security functions. In an example, upon completion of NAS security function setup, the AMF 155 may initiate NGAP procedure to enable 5G-AN use it for securing procedures with the UE. In an example, the 5G-AN may store the security context and may acknowledge to the AMF 155. The 5G-AN may use the security context to protect the messages exchanged with the UE.

In an example, new AMF 155 may send to the old AMF 155 Namf_Communication_RegistrationCompleteNotify. If the AMF 155 has changed, the new AMF 155 may notify the old AMF 155 that the registration of the UE 100 in the new AMF 155 may be completed by invoking the Namf_Communication_RegistrationCompleteNotify service operation. If the authentication/security procedure fails, then the registration may be rejected, and the new AMF 155 may invoke the Namf_Communication_RegistrationCompleteNotify service operation with a reject indication reason code towards the old AMF 155. The old AMF 155 may continue as if the UE 100 context transfer service operation was never received. If one or more of the S-NSSAIs used in the old registration area may not be served in the target registration area, the new AMF 155 may determine which PDU session may not be supported in the new registration area. The new AMF 155 may invoke the Namf_Communication_RegistrationCompleteNotify service operation including the rejected PDU session ID and a reject cause (e.g. the S-NSSAI becomes no longer available) towards the old AMF 155. The new AMF 155 may modify the PDU session status correspondingly. The old AMF 155 may inform the corresponding SMF 160(s) to locally release the UE's SM context by invoking the Nsmf_PDUSession_ReleaseSMContext service operation.

In an example, the new AMF 155 may send to the UE 100 an identity request/response (e.g., PEI). If the PEI was not provided by the UE 100 nor retrieved from the old AMF 155, the identity request procedure may be initiated by AMF 155 sending an identity request message to the UE 100 to retrieve the PEI. The PEI may be transferred encrypted unless the UE 100 performs emergency registration and may not be authenticated. For an emergency registration, the UE 100 may have included the PEI in the registration request.

In an example, the new AMF 155 may initiate ME identity check by invoking the N5g-eir_EquipmentIdentityCheck_Get service operation.

In an example, the new AMF 155, based on the SUPI, may select a UDM 140. The UDM 140 may select a UDR instance. In an example, the AMF 155 may selects a UDM 140.

In an example, if the AMF 155 has changed since the last registration procedure, or if the UE 100 provides a SUPI which may not refer to a valid context in the AMF 155, or if the UE 100 registers to the same AMF 155 it has already registered to a non-3GPP access (e.g., the UE 100 is registered over a non-3GPP access and may initiate the registration procedure to add a 3GPP access), the new AMF 155 may register with the UDM 140 using Nudm_UECM_Registration and may subscribe to be notified when the UDM 140 may deregister the AMF 155. The UDM 140 may store the AMF 155 identity associated to the access type and may not remove the AMF 155 identity associated to the other access type. The UDM 140 may store information provided at registration in UDR, by Nudr_UDM_Update. In an example, the AMF 155 may retrieve the access and mobility subscription data and SMF 160 selection subscription data using Nudm_SDM_Get. The UDM 140 may retrieve this information from UDR by Nudr_UDM_Query (access and mobility subscription data). After a successful response is received, the AMF 155 may subscribe to be notified using Nudm_SDM_Subscribe when the data requested may be modified. The UDM 140 may subscribe to UDR by Nudr_UDM_Subscribe. The GPSI may be provided to the AMF 155 in the subscription data from the UDM 140 if the GPSI is available in the UE 100 subscription data. In an example, the new AMF 155 may provide the access type it serves for the UE 100 to the UDM 140 and the access type may be set to 3GPP access. The UDM 140 may store the associated access type together with the serving AMF 155 in UDR by Nudr_UDM_Update. The new AMF 155 may create an MM context for the UE 100 after getting the mobility subscription data from the UDM 140. In an example, when the UDM 140 stores the associated access type together with the serving AMF 155, the UDM 140 may initiate a Nudm_UECM_DeregistrationNotification to the old AMF 155 corresponding to 3GPP access. The old AMF 155 may remove the MM context of the UE. If the serving NF removal reason indicated by the UDM 140 is initial registration, then the old AMF 155 may invoke the Namf_EventExposure_Notify service operation towards all the associated SMF 160 s of the UE 100 to notify that the UE 100 is deregistered from old AMF 155. The SMF 160 may release the PDU session(s) on getting this notification. In an example, the old AMF 155 may unsubscribe with the UDM 140 for subscription data using Nudm_SDM_unsubscribe.

In an example, if the AMF 155 decides to initiate PCF 135 communication, e.g. the AMF 155 has not yet obtained access and mobility policy for the UE 100 or if the access and mobility policy in the AMF 155 are no longer valid, the AMF 155 may select a PCF 135. If the new AMF 155 receives a PCF ID from the old AMF 155 and successfully contacts the PCF 135 identified by the PCF ID, the AMF 155 may select the (V-)PCF identified by the PCF ID. If the PCF 135 identified by the PCF ID may not be used (e.g. no response from the PCF 135) or if there is no PCF ID received from the old AMF 155, the AMF 155 may select a PCF 135.

In an example, the new AMF 155 may perform a policy association establishment during registration procedure. If the new AMF 155 contacts the PCF 135 identified by the (V-)PCF ID received during inter-AMF 155 mobility, the new AMF 155 may include the PCF-ID in the Npcf_AMPolicyControl Get operation. If the AMF 155 notifies the mobility restrictions (e.g. UE 100 location) to the PCF 135 for adjustment, or if the PCF 135 updates the mobility restrictions itself due to some conditions (e.g. application in use, time and date), the PCF 135 may provide the updated mobility restrictions to the AMF 155.

In an example, the PCF 135 may invoke Namf_EventExposure_Subscribe service operation for UE 100 event subscription.

In an example, the AMF 155 may send to the SMF 160 an Nsmf_PDUSession_UpdateSMContext. In an example, the AMF 155 may invoke the Nsmf_PDUSession_UpdateSMContext if the PDU session(s) to be re-activated is included in the registration request. The AMF 155 may send Nsmf_PDUSession_UpdateSMContext request to SMF 160(s) associated with the PDU session(s) to activate user plane connections of the PDU session(s). The SMF 160 may decide to trigger e.g. the intermediate UPF 110 insertion, removal or change of PSA. In the case that the intermediate UPF 110 insertion, removal, or relocation is performed for the PDU session(s) not included in PDU session(s) to be re-activated, the procedure may be performed without N11 and N2 interactions to update the N3 user plane between (R)AN 105 and 5GC. The AMF 155 may invoke the Nsmf_PDUSession_ReleaseSMContext service operation towards the SMF 160 if any PDU session status indicates that it is released at the UE 100. The AMF 155 may invoke the Nsmf_PDUSession_ReleaseSMContext service operation towards the SMF 160 in order to release any network resources related to the PDU session.

In an example, the new AMF 155155 may send to a N3IWF an N2 AMF 155 mobility request. If the AMF 155 has changed, the new AMF 155 may create an NGAP UE 100 association towards the N3IWF to which the UE 100 is connected. In an example, the N3IWF may respond to the new AMF 155 with an N2 AMF 155 mobility response.

In an example, the new AMF 155 may send to the UE 100 a registration accept (comprising: 5G-GUTI, registration area, mobility restrictions, PDU session status, allowed NSSAI, [mapping of allowed NSSAI], periodic registration update timer, LADN information and accepted MICO mode, IMS voice over PS session supported indication, emergency service support indicator, and/or the like). In an example, the AMF 155 may send the registration accept message to the UE 100 indicating that the registration request has been accepted. 5G-GUTI may be included if the AMF 155 allocates a new 5G-GUTI. If the AMF 155 allocates a new registration area, it may send the registration area to the UE 100 via registration accept message. If there is no registration area included in the registration accept message, the UE 100 may consider the old registration area as valid. In an example, mobility restrictions may be included in case mobility restrictions may apply for the UE 100 and registration type may not be emergency registration. The AMF 155 may indicate the established PDU sessions to the UE 100 in the PDU session status. The UE 100 may remove locally any internal resources related to PDU sessions that are not marked as established in the received PDU session status. In an example, when the UE 100 is connected to the two AMF 155 belonging to different PLMN via 3GPP access and non-3GPP access then the UE 100 may remove locally any internal resources related to the PDU session of the current PLMN that are not marked as established in received PDU session status. If the PDU session status information was in the registration request, the AMF 155 may indicate the PDU session status to the UE. The mapping of allowed NSSAI may be the mapping of each S-NSSAI of the allowed NSSAI to the S-NSSAIs of the configured NSSAI for the HPLMN. The AMF 155 may include in the registration accept message the LADN information for LADNs that are available within the registration area determined by the AMF 155 for the UE. If the UE 100 included MICO mode in the request, then AMF 155 may respond whether MICO mode may be used. The AMF 155 may set the IMS voice over PS session supported Indication. In an example, in order to set the IMS voice over PS session supported indication, the AMF 155 may perform a UE/RAN radio information and compatibility request procedure to check the compatibility of the UE 100 and RAN radio capabilities related to IMS voice over PS. In an example, the emergency service support indicator may inform the UE 100 that emergency services are supported, e.g., the UE 100 may request PDU session for emergency services. In an example, the handover restriction list and UE-AMBR may be provided to NG-RAN by the AMF 155.

In an example, the UE 100 may send to the new AMF 155 a registration complete message. In an example, the UE 100 may send the registration complete message to the AMF 155 to acknowledge that a new 5G-GUTI may be assigned. In an example, when information about the PDU session(s) to be re-activated is not included in the registration request, the AMF 155 may release the signaling connection with the UE 100. In an example, when the follow-on request is included in the registration request, the AMF 155 may not release the signaling connection after the completion of the registration procedure. In an example, if the AMF 155 is aware that some signaling is pending in the AMF 155 or between the UE 100 and the 5GC, the AMF 155 may not release the signaling connection after the completion of the registration procedure.

As depicted in example FIG. 10 and FIG. 11 , a service request procedure e.g., a UE 100 triggered service request procedure may be used by a UE 100 in CM-IDLE state to request the establishment of a secure connection to an AMF 155. FIG. 11 is continuation of FIG. 10 depicting the service request procedure. The service request procedure may be used to activate a user plane connection for an established PDU session. The service request procedure may be triggered by the UE 100 or the 5GC, and may be used when the UE 100 is in CM-IDLE and/or in CM-CONNECTED and may allow selectively to activate user plane connections for some of the established PDU sessions.

In an example, a UE 100 in CM IDLE state may initiate the service request procedure to send uplink signaling messages, user data, and/or the like, as a response to a network paging request, and/or the like. In an example, after receiving the service request message, the AMF 155 may perform authentication. In an example, after the establishment of signaling connection to the AMF 155, the UE 100 or network may send signaling messages, e.g. PDU session establishment from the UE 100 to a SMF 160, via the AMF 155.

In an example, for any service request, the AMF 155 may respond with a service accept message to synchronize PDU session status between the UE 100 and network. The AMF 155 may respond with a service reject message to the UE 100, if the service request may not be accepted by the network. The service reject message may include an indication or cause code requesting the UE 100 to perform a registration update procedure. In an example, for service request due to user data, network may take further actions if user plane connection activation may not be successful. In an example FIG. 10 and FIG. 11 , more than one UPF, e.g., old UPF 110-2 and PDU session Anchor PSA UPF 110-3 may be involved.

In an example, the UE 100 may send to a (R)AN 105 an AN message comprising AN parameters, mobility management, MM NAS service request (e.g., list of PDU sessions to be activated, list of allowed PDU sessions, security parameters, PDU session status, and/or the like), and/or the like. In an example, the UE 100 may provide the list of PDU sessions to be activated when the UE 100 may re-activate the PDU session(s). The list of allowed PDU sessions may be provided by the UE 100 when the service request may be a response of a paging or a NAS notification, and may identify the PDU sessions that may be transferred or associated to the access on which the service request may be sent. In an example, for the case of NG-RAN, the AN parameters may include selected PLMN ID, and an establishment cause. The establishment cause may provide the reason for requesting the establishment of an RRC connection. The UE 100 may send NAS service request message towards the AMF 155 encapsulated in an RRC message to the RAN 105.

In an example, if the service request may be triggered for user data, the UE 100 may identify, using the list of PDU sessions to be activated, the PDU session(s) for which the UP connections are to be activated in the NAS service request message. If the service request may be triggered for signaling, the UE 100 may not identify any PDU session(s). If this procedure may be triggered for paging response, and/or the UE 100 may have at the same time user data to be transferred, the UE 100 may identify the PDU session(s) whose UP connections may be activated in MM NAS service request message, by the list of PDU sessions to be activated.

In an example, if the service request over 3GPP access may be triggered in response to a paging indicating non-3GPP access, the NAS service request message may identify in the list of allowed PDU sessions the list of PDU sessions associated with the non-3GPP access that may be re-activated over 3GPP. In an example, the PDU session status may indicate the PDU sessions available in the UE 100. In an example, the UE 100 may not trigger the service request procedure for a PDU session corresponding to a LADN when the UE 100 may be outside the area of availability of the LADN. The UE 100 may not identify such PDU session(s) in the list of PDU sessions to be activated, if the service request may be triggered for other reasons.

In an example, the (R)AN 105 may send to AMF 155 an N2 Message (e.g., a service request) comprising N2 parameters, MM NAS service request, and/or the like. The AMF 155 may reject the N2 message if it may not be able to handle the service request. In an example, if NG-RAN may be used, the N2 parameters may include the 5G-GUTI, selected PLMN ID, location information, RAT type, establishment cause, and/or the like. In an example, the 5G-GUTI may be obtained in RRC procedure and the (R)AN 105 may select the AMF 155 according to the 5G-GUTI. In an example, the location information and RAT type may relate to the cell in which the UE 100 may be camping. In an example, based on the PDU session status, the AMF 155 may initiate PDU session release procedure in the network for the PDU sessions whose PDU session ID(s) may be indicated by the UE 100 as not available.

In an example, if the service request was not sent integrity protected or integrity protection verification failed, the AMF 155 may initiate a NAS authentication/security procedure.

In an example, if the UE 100 triggers the service request to establish a signaling connection, upon successful establishment of the signaling connection, the UE 100 and the network may exchange NAS signaling.

In an example the AMF 155 may send to the SMF 160 a PDU session update context request 1020 e.g., Nsmf_PDUSession_UpdateSMContext request comprising PDU session ID(s), Cause(s), UE 100 location information, access type, and/or the like.

In an example, the Nsmf_PDUSession_UpdateSMContext request may be invoked by the AMF 155 if the UE 100 may identify PDU session(s) to be activated in the NAS service request message. In an example, the Nsmf_PDUSession_UpdateSMContext request may be triggered by the SMF 160 wherein the PDU session(s) identified by the UE 100 may correlate to other PDU session ID(s) than the one triggering the procedure. In an example, the Nsmf_PDUSession_UpdateSMContext request may be triggered by the SMF 160 wherein the current UE 100 location may be outside the area of validity for the N2 information provided by the SMF 160 during a network triggered service request procedure. The AMF 155 may not send the N2 information provided by the SMF 160 during the network triggered service request procedure.

In an example, the AMF 155 may determine the PDU session(s) to be activated and may send an Nsmf_PDUSession_UpdateSMContext request to SMF 160(s) associated with the PDU session(s) with cause set to indicate establishment of user plane resources for the PDU session(s).

In an example, if the procedure may be triggered in response to paging indicating non-3GPP access, and the list of allowed PDU sessions provided by the UE 100 may not include the PDU session for which the UE 100 was paged, the AMF 155 may notify the SMF 160 that the user plane for the PDU session may not be re-activated. The service request procedure may succeed without re-activating the user plane of any PDU sessions, and the AMF 155 may notify the UE 100.

In an example, if the PDU session ID may correspond to a LADN and the SMF 160 may determine that the UE 100 may be outside the area of availability of the LADN based on the UE 100 location reporting from the AMF 155, the SMF 160 may decide to (based on local policies) keep the PDU session, may reject the activation of user plane connection for the PDU session and may inform the AMF 155. In an example, if the procedure may be triggered by a network triggered service request, the SMF 160 may notify the UPF 110 that originated the data notification to discard downlink data for the PDU sessions and/or to not provide further data notification messages. The SMF 160 may respond to the AMF 155 with an appropriate reject cause and the user plane activation of PDU session may be stopped.

In an example, if the PDU session ID may correspond to a LADN and the SMF 160 may determine that the UE 100 may be outside the area of availability of the LADN based on the UE 100 location reporting from the AMF 155, the SMF 160 may decide to (based on local policies) release the PDU session. The SMF 160 may locally release the PDU session and may inform the AMF 155 that the PDU session may be released. The SMF 160 may respond to the AMF 155 with an appropriate reject cause and the user plane Activation of PDU session may be stopped.

In an example, if the UP activation of the PDU session may be accepted by the SMF 160, based on the location info received from the AMF 155, the SMF 160 may check the UPF 110 Selection Criteria (e.g., slice isolation requirements, slice coexistence requirements, UPF's 110 dynamic load, UPF's 110 relative static capacity among UPFs supporting the same DNN, UPF 110 location available at the SMF 160, UE 100 location information, Capability of the UPF 110 and the functionality required for the particular UE 100 session. In an example, an appropriate UPF 110 may be selected by matching the functionality and features required for a UE 100, DNN, PDU session type (i.e. IPv4, IPv6, ethernet type or unstructured type) and if applicable, the static IP address/prefix, SSC mode selected for the PDU session, UE 100 subscription profile in UDM 140, DNAI as included in the PCC rules, local operator policies, S-NSSAI, access technology being used by the UE 100, UPF 110 logical topology, and/or the like), and may determine to perform one or more of the following: continue using the current UPF(s); may select a new intermediate UPF 110 (or add/remove an intermediate UPF 110), if the UE 100 has moved out of the service area of the UPF 110 that was previously connecting to the (R)AN 105, while maintaining the UPF(s) acting as PDU session anchor; may trigger re-establishment of the PDU session to perform relocation/reallocation of the UPF 110 acting as PDU session anchor, e.g. the UE 100 has moved out of the service area of the anchor UPF 110 which is connecting to RAN 105.

In an example, the SMF 160 may send to the UPF 110 (e.g., new intermediate UPF 110) an N4 session establishment request. In an example, if the SMF 160 may select a new UPF 110 to act as intermediate UPF 110-2 for the PDU session, or if the SMF 160 may select to insert an intermediate UPF 110 for a PDU session which may not have an intermediate UPF 110-2, an N4 session establishment request message may be sent to the new UPF 110, providing packet detection, data forwarding, enforcement and reporting rules to be installed on the new intermediate UPF. The PDU session anchor addressing information (on N9) for this PDU session may be provided to the intermediate UPF 110-2.

In an example, if a new UPF 110 is selected by the SMF 160 to replace the old (intermediate) UPF 110-2, the SMF 160 may include a data forwarding indication. The data forwarding indication may indicate to the UPF 110 that a second tunnel endpoint may be reserved for buffered DL data from the old I-UPF.

In an example, the new UPF 110 (intermediate) may send to SMF 160 an N4 session establishment response message. In case the UPF 110 may allocate CN tunnel info, the UPF 110 may provide DL CN tunnel info for the UPF 110 acting as PDU session anchor and UL CN tunnel info (e.g., CN N3 tunnel info) to the SMF 160. If the data forwarding indication may be received, the new (intermediate) UPF 110 acting as N3 terminating point may send DL CN tunnel info for the old (intermediate) UPF 110-2 to the SMF 160. The SMF 160 may start a timer, to release the resource in the old intermediate UPF 110-2.

In an example, if the SMF 160 may selects a new intermediate UPF 110 for the PDU session or may remove the old I-UPF 110-2, the SMF 160 may send N4 session modification request message to PDU session anchor, PSA UPF 110-3, providing the data forwarding indication and DL tunnel information from new intermediate UPF 110.

In an example, if the new intermediate UPF 110 may be added for the PDU session, the (PSA) UPF 110-3 may begin to send the DL data to the new I-UPF 110 as indicated in the DL tunnel information.

In an example, if the service request may be triggered by the network, and the SMF 160 may remove the old I-UPF 110-2 and may not replace the old I-UPF 110-2 with the new I-UPF 110, the SMF 160 may include the data forwarding indication in the request. The data forwarding indication may indicate to the (PSA) UPF 110-3 that a second tunnel endpoint may be reserved for buffered DL data from the old I-UPF 110-2. In this case, the PSA UPF 110-3 may begin to buffer the DL data it may receive at the same time from the N6 interface.

In an example, the PSA UPF 110-3 (PSA) may send to the SMF 160 an N4 session modification response. In an example, if the data forwarding indication may be received, the PSA UPF 110-3 may become as N3 terminating point and may send CN DL tunnel info for the old (intermediate) UPF 110-2 to the SMF 160. The SMF 160 may start a timer, to release the resource in old intermediate UPF 110-2 if there is one.

In an example, the SMF 160 may send to the old UPF 110-2 an N4 session modification request (e.g., may comprise new UPF 110 address, new UPF 110 DL tunnel ID, and/or the like). In an example, if the service request may be triggered by the network, and/or the SMF 160 may remove the old (intermediate) UPF 110-2, the SMF 160 may send the N4 session modification request message to the old (intermediate) UPF 110-2, and may provide the DL tunnel information for the buffered DL data. If the SMF 160 may allocate new I-UPF 110, the DL tunnel information is from the new (intermediate) UPF 110 may act as N3 terminating point. If the SMF 160 may not allocate a new I-UPF 110, the DL tunnel information may be from the new UPF 110 (PSA) 110-3 acting as N3 terminating point. The SMF 160 may start a timer to monitor the forwarding tunnel. In an example, the old (intermediate) UPF 110-2 may send N4 session modification response message to the SMF 160.

In an example, if the I-UPF 110-2 may be relocated and forwarding tunnel was established to the new I-UPF 110, the old (intermediate) UPF 110-2 may forward its buffered data to the new (intermediate) UPF 110 acting as N3 terminating point. In an example, if the old I-UPF 110-2 may be removed and the new I-UPF 110 may not be assigned for the PDU session and forwarding tunnel may be established to the UPF 110 (PSA) 110-3, the old (intermediate) UPF 110-2 may forward its buffered data to the UPF 110 (PSA) 110-3 acting as N3 terminating point.

In an example, the SMF 160 may send to the AMF 155 an N11 message e.g., a Nsmf_PDUSession_UpdateSMContext response (comprising: N1 SM container (PDU session ID, PDU session re-establishment indication), N2 SM information (PDU session ID, QoS profile, CN N3 tunnel info, S-NSSAI), Cause), upon reception of the Nsmf_PDUSession_UpdateSMContext request with a cause including e.g., establishment of user plane resources. The SMF 160 may determine whether UPF 110 reallocation may be performed, based on the UE 100 location information, UPF 110 service area and operator policies. In an example, for a PDU session that the SMF 160 may determine to be served by the current UPF 110, e.g., PDU session anchor or intermediate UPF, the SMF 160 may generate N2 SM information and may send an Nsmf_PDUSession_UpdateSMContext response to the AMF 155 to establish the user plane(s). The N2 SM information may contain information that the AMF 155 may provide to the RAN 105. In an example, for a PDU session that the SMF 160 may determine as requiring a UPF 110 relocation for PDU session anchor UPF, the SMF 160 may reject the activation of UP of the PDU session by sending Nsmf_PDUSession_UpdateSMContext response that may contain N1 SM container to the UE 100 via the AMF 155. The N1 SM container may include the corresponding PDU session ID and PDU session re-establishment indication.

Upon reception of the Namf_EventExposure_Notify from the AMF 155 to the SMF 160, with an indication that the UE 100 is reachable, if the SMF 160 may have pending DL data, the SMF 160 may invoke the Namf_Communication_N1N2MessageTransfer service operation to the AMF 155 to establish the user plane(s) for the PDU sessions. In an example, the SMF 160 may resume sending DL data notifications to the AMF 155 in case of DL data.

In an example, the SMF 160 may send a message to the AMF 155 to reject the activation of UP of the PDU session by including a cause in the Nsmf_PDUSession_UpdateSMContext response if the PDU session may correspond to a LADN and the UE 100 may be outside the area of availability of the LADN, or if the AMF 155 may notify the SMF 160 that the UE 100 may be reachable for regulatory prioritized service, and the PDU session to be activated may not for a regulatory prioritized service; or if the SMF 160 may decide to perform PSA UPF 110-3 relocation for the requested PDU session.

In an example, the AMF 155 may send to the (R)AN 105 an N2 request message (e.g., N2 SM information received from SMF 160, security context, AMF 155 signaling connection ID, handover restriction list, MM NAS service accept, list of recommended cells/TAs/NG-RAN node identifiers). In an example, the RAN 105 may store the security context, AMF 155 signaling connection Id, QoS information for the QoS flows of the PDU sessions that may be activated and N3 tunnel IDs in the UE 100 RAN 105 context. In an example, the MM NAS service accept may include PDU session status in the AMF 155. If the activation of UP of a PDU session may be rejected by the SMF 160, the MM NAS service accept may include the PDU session ID and the reason why the user plane resources may not be activated (e.g. LADN not available). Local PDU session release during the session request procedure may be indicated to the UE 100 via the session Status.

In an example, if there are multiple PDU sessions that may involve multiple SMF 160 s, the AMF 155 may not wait for responses from all SMF 160 s before it may send N2 SM information to the UE 100. The AMF 155 may wait for all responses from the SMF 160 s before it may send MM NAS service accept message to the UE 100.

In an example, the AMF 155 may include at least one N2 SM information from the SMF 160 if the procedure may be triggered for PDU session user plane activation. AMF 155 may send additional N2 SM information from SMF 160 s in separate N2 message(s) (e.g. N2 tunnel setup request), if there is any. Alternatively, if multiple SMF 160 s may be involved, the AMF 155 may send one N2 request message to (R)AN 105 after all the Nsmf_PDUSession_UpdateSMContext response service operations from all the SMF 160 s associated with the UE 100 may be received. In such case, the N2 request message may include the N2 SM information received in each of the Nsmf_PDUSession_UpdateSMContext response and PDU session ID to enable AMF 155 to associate responses to relevant SMF 160.

In an example, if the RAN 105 (e.g., NG RAN) node may provide the list of recommended cells/TAs/NG-RAN node identifiers during the AN release procedure, the AMF 155 may include the information from the list in the N2 request. The RAN 105 may use this information to allocate the RAN 105 notification area when the RAN 105 may decide to enable RRC inactive state for the UE 100.

If the AMF 155 may receive an indication, from the SMF 160 during a PDU session establishment procedure that the UE 100 may be using a PDU session related to latency sensitive services, for any of the PDU sessions established for the UE 100 and the AMF 155 has received an indication from the UE 100 that may support the CM-CONNECTED with RRC inactive state, then the AMF 155 may include the UE's RRC inactive assistance information. In an example, the AMF 155 based on network configuration, may include the UE's RRC inactive assistance information.

In an example, the (R)AN 105 may send to the UE 100 a message to perform RRC connection reconfiguration with the UE 100 depending on the QoS information for all the QoS flows of the PDU sessions whose UP connections may be activated and data radio bearers. In an example, the user plane security may be established.

In an example, if the N2 request may include a MM NAS service accept message, the RAN 105 may forward the MM NAS service accept to the UE 100. The UE 100 may locally delete context of PDU sessions that may not be available in 5GC.

In an example, if the N1 SM information may be transmitted to the UE 100 and may indicate that some PDU session(s) may be re-established, the UE 100 may initiate PDU session re-establishment for the PDU session(s) that may be re-established after the service request procedure may be complete.

In an example, after the user plane radio resources may be setup, the uplink data from the UE 100 may be forwarded to the RAN 105. The RAN 105 (e.g., NG-RAN) may send the uplink data to the UPF 110 address and tunnel ID provided.

In an example, the (R)AN 105 may send to the AMF 155 an N2 request Ack (e.g., N2 SM information (comprising: AN tunnel info, list of accepted QoS flows for the PDU sessions whose UP connections are activated, list of rejected QoS flows for the PDU sessions whose UP connections are activated)). In an example, the N2 request message may include N2 SM information(s), e.g. AN tunnel info. RAN 105 may respond N2 SM information with separate N2 message (e.g. N2 tunnel setup response). In an example, if multiple N2 SM information are included in the N2 request message, the N2 request Ack may include multiple N2 SM information and information to enable the AMF 155 to associate the responses to relevant SMF 160.

In an example, the AMF 155 may send to the SMF 160 a Nsmf_PDUSession_UpdateSMContext request (N2 SM information (AN tunnel info), RAT type) per PDU session. If the AMF 155 may receive N2 SM information (one or multiple) from the RAN 105, then the AMF 155 may forward the N2 SM information to the relevant SMF 160. If the UE 100 time zone may change compared to the last reported UE 100 Time Zone then the AMF 155 may include the UE 100 time zone IE in the Nsmf_PDUSession_UpdateSMContext request message.

In an example, if dynamic PCC is deployed, the SMF 160 may initiate notification about new location information to the PCF 135 (if subscribed) by invoking an event exposure notification operation (e.g., a Nsmf_EventExposure_Notify service operation). The PCF 135 may provide updated policies by invoking a policy control update notification message (e.g., a Npcf_SMPolicyControl_UpdateNotify operation).

In an example, if the SMF 160 may select a new UPF 110 to act as intermediate UPF 110 for the PDU session, the SMF 160 may initiates an N4 session modification procedure to the new I-UPF 110 and may provide AN tunnel info. The downlink data from the new I-UPF 110 may be forwarded to RAN 105 and UE 100. In an example, the UPF 110 may send to the SMF 160, an N4 session modification response. In an example, the SMF 160 may send to the AMF 155, an Nsmf_PDUSession_UpdateSMContext response.

In an example, if forwarding tunnel may be established to the new I-UPF 110 and if the timer SMF 160 set for forwarding tunnel may be expired, the SMF 160 may sends N4 session modification request to new (intermediate) UPF 110 acting as N3 terminating point to release the forwarding tunnel. In an example, the new (intermediate) UPF 110 may send to the SMF 160 an N4 session modification response. In an example, the SMF 160 may send to the PSA UPF 110-3 an N4 session modification request, or N4 session release request. In an example, if the SMF 160 may continue using the old UPF 110-2, the SMF 160 may send an N4 session modification request, providing AN tunnel info. In an example, if the SMF 160 may select a new UPF 110 to act as intermediate UPF 110, and the old UPF 110-2 may not be PSA UPF 110-3, the SMF 160 may initiate resource release, after timer expires, by sending an N4 session release request (release cause) to the old intermediate UPF 110-2.

In an example, the old intermediate UPF 110-2 may send to the SMF 160 an N4 session modification response or N4 session release response. The old UPF 110-2 may acknowledge with the N4 session modification response or N4 session release response message to confirm the modification or release of resources. The AMF 155 may invoke the Namf_EventExposure_Notify service operation to notify the mobility related events, after this procedure may complete, towards the NFs that may have subscribed for the events. In an example, the AMF 155 may invoke the Namf_EventExposure_Notify towards the SMF 160 if the SMF 160 had subscribed for UE 100 moving into or out of area of interest and if the UE's current location may indicate that it may be moving into or moving outside of the area of interest subscribed, or if the SMF 160 had subscribed for LADN DNN and if the UE 100 may be moving into or outside of an area where the LADN is available, or if the UE 100 may be in MICO mode and the AMF 155 had notified an SMF 160 of the UE 100 being unreachable and that SMF 160 may not send DL data notifications to the AMF 155, and the AMF 155 may informs the SMF 160 that the UE 100 is reachable, or if the SMF 160 had subscribed for UE 100 reachability status, then the AMF 155 may notify the UE 100 reachability.

An example PDU session establishment procedure depicted in FIG. 12 and FIG. 13 . In an example embodiment, when the PDU session establishment procedure may be employed, the UE 100 may send to the AMF 155 a NAS Message (or a SM NAS message) comprising NSSAI, S-NSSAI (e.g., requested S-NSSAI, allowed S-NSSAI, subscribed S-NSSAI, and/or the like), DNN, PDU session ID, request type, old PDU session ID, N1 SM container (PDU session establishment request), and/or the like. In an example, the UE 100, in order to establish a new PDU session, may generate a new PDU session ID. In an example, when emergency service may be required and an emergency PDU session may not already be established, the UE 100 may initiate the UE 100 requested PDU session establishment procedure with a request type indicating emergency request. In an example, the UE 100 may initiate the UE 100 requested PDU session establishment procedure by the transmission of the NAS message containing a PDU session establishment request within the N1 SM container. The PDU session establishment request may include a PDU type, SSC mode, protocol configuration options, and/or the like. In an example, the request type may indicate initial request if the PDU session establishment is a request to establish the new PDU session and may indicate existing PDU session if the request refers to an existing PDU session between 3GPP access and non-3GPP access or to an existing PDN connection in EPC. In an example, the request type may indicate emergency request if the PDU session establishment may be a request to establish a PDU session for emergency services. The request type may indicate existing emergency PDU session if the request refers to an existing PDU session for emergency services between 3GPP access and non-3GPP access. In an example, the NAS message sent by the UE 100 may be encapsulated by the AN in a N2 message towards the AMF 155 that may include user location information and access technology type information. In an example, the PDU session establishment request message may contain SM PDU DN request container containing information for the PDU session authorization by the external DN. In an example, if the procedure may be triggered for SSC mode 3 operation, the UE 100 may include the old PDU session ID which may indicate the PDU session ID of the on-going PDU session to be released, in the NAS message. The old PDU session ID may be an optional parameter which may be included in this case. In an example, the AMF 155 may receive from the AN the NAS message (e.g., NAS SM message) together with user location information (e.g. cell ID in case of the RAN 105). In an example, the UE 100 may not trigger a PDU session establishment for a PDU session corresponding to a LADN when the UE 100 is outside the area of availability of the LADN.

In an example, the AMF 155 may determine that the NAS message or the SM NAS message may correspond to the request for the new PDU session based on that request type indicates initial request and that the PDU session ID may not be used for any existing PDU session(s) of the UE 100. If the NAS message does not contain an S-NSSAI, the AMF 155 may determine a default S-NSSAI for the requested PDU session either according to the UE 100 subscription, if it may contain only one default S-NSSAI, or based on operator policy. In an example, the AMF 155 may perform an SMF 160 selection and select an SMF 160. If the request type may indicate initial request or the request may be due to handover from EPS, the AMF 155 may store an association of the S-NSSAI, the PDU session ID and a SMF 160 ID. In an example, if the request type is initial request and if the old PDU session ID indicating the existing PDU session may be contained in the message, the AMF 155 may select the SMF 160 and may store an association of the new PDU session ID and the selected SMF 160 ID.

In an example, the AMF 155 may send to the SMF 160, an N11 message, e.g., Nsmf_PDUSession_CreateSMContext request (comprising: SUPI or PEI, DNN, S-NSSAI, PDU session ID, AMF 155 ID, request type, N1 SM container (PDU session establishment request), user location information, access type, PEI, GPSI), or Nsmf_PDUSession_UpdateSMContext request (SUPI, DNN, S-NSSAI, PDU session ID, AMF 155 ID, request type, N1 SM container (PDU session establishment request), user location information, access type, RAT type, PEI). In an example, if the AMF 155 may not have an association with the SMF 160 for the PDU session ID provided by the UE 100 (e.g. when request type indicates initial request), the AMF 155 may invoke the Nsmf_PDUSession_CreateSMContext request, but if the AMF 155 already has an association with an SMF 160 for the PDU session ID provided by the UE 100 (e.g. when request type indicates existing PDU session), the AMF 155 may invoke the Nsmf_PDUSession_UpdateSMContext request. In an example, the AMF 155 ID may be the UE's GUAMI which uniquely identifies the AMF 155 serving the UE 100. The AMF 155 may forward the PDU session ID together with the N1 SM container containing the PDU session establishment request received from the UE 100. The AMF 155 may provide the PEI instead of the SUPI when the UE 100 has registered for emergency services without providing the SUPI. In case the UE 100 has registered for emergency services but has not been authenticated, the AMF 155 may indicate that the SUPI has not been authenticated.

In an example, if the request type may indicate neither emergency request nor existing emergency PDU session and, if the SMF 160 has not yet registered and subscription data may not be available, the SMF 160 may register with the UDM 140, and may retrieve subscription data and subscribes to be notified when subscription data may be modified. In an example, if the request type may indicate existing PDU session or existing emergency PDU session, the SMF 160 may determine that the request may be due to handover between 3GPP access and non-3GPP access or due to handover from EPS. The SMF 160 may identify the existing PDU session based on the PDU session ID. The SMF 160 may not create a new SM context but instead may update the existing SM context and may provide the representation of the updated SM context to the AMF 155 in the response. if the request type may be initial request and if the old PDU session ID may be included in Nsmf_PDUSession_CreateSMContext request, the SMF 160 may identify the existing PDU session to be released based on the old PDU session ID.

In an example, the SMF 160 may send to the AMF 155, the N11 message response, e.g., either a PDU session create/update response, Nsmf_PDUSession_CreateSMContext response (cause, SM context ID or N1 SM container (PDU session reject(cause))) or an Nsmf_PDUSession_UpdateSMContext response.

In an example, if the SMF 160 may perform secondary authorization/authentication during the establishment of the PDU session by a DN-AAA server, the SMF 160 may select a UPF 110 and may trigger a PDU session establishment authentication/authorization.

In an example, if the request type may indicate initial request, the SMF 160 may select an SSC mode for the PDU session. The SMF 160 may select one or more UPFs as needed. In case of PDU type IPv4 or IPv6, the SMF 160 may allocate an IP address/prefix for the PDU session. In case of PDU type IPv6, the SMF 160 may allocate an interface identifier to the UE 100 for the UE 100 to build its link-local address. For Unstructured PDU type the SMF 160 may allocate an IPv6 prefix for the PDU session and N6 point-to-point tunneling (based on UDP/IPv6).

In an example, if dynamic PCC is deployed, the may SMF 160 performs PCF 135 selection. If the request type indicates existing PDU session or existing emergency PDU session, the SMF 160 may use the PCF 135 already selected for the PDU session. If dynamic PCC is not deployed, the SMF 160 may apply local policy.

In an example, the SMF 160 may perform a session management policy establishment procedure to establish a PDU session with the PCF 135 and may get the default PCC Rules for the PDU session. The GPSI may be included if available at the SMF 160. If the request type in indicates existing PDU session, the SMF 160 may notify an event previously subscribed by the PCF 135 by a session management policy modification procedure and the PCF 135 may update policy information in the SMF 160. The PCF 135 may provide authorized session-AMBR and the authorized 5QI and ARP to SMF 160. The PCF 135 may subscribe to the IP allocation/release event in the SMF 160 (and may subscribe other events).

In an example, the PCF 135, based on the emergency DNN, may set the ARP of the PCC rules to a value that may be reserved for emergency services.

In an example, if the request type indicates initial request, the SMF 160 may select an SSC mode for the PDU session. The SMF 160 may select one or more UPFs as needed. In case of PDU type IPv4 or IPv6, the SMF 160 may allocate an IP address/prefix for the PDU session. In case of PDU type IPv6, the SMF 160 may allocate an interface identifier to the UE 100 for the UE 100 to build its link-local address. For unstructured PDU type the SMF 160 may allocate an IPv6 prefix for the PDU session and N6 point-to-point tunneling (e.g., based on UDP/IPv6). In an example, for Ethernet PDU type PDU session, neither a MAC nor an IP address may be allocated by the SMF 160 to the UE 100 for this PDU session.

In an example, if the request type is existing PDU session, the SMF 160 may maintain the same IP address/prefix that may be allocated to the UE 100 in the source network.

In an example, if the request type indicates existing PDU session referring to an existing PDU session moved between 3GPP access and non-3GPP access, the SMF 160 may maintain the SSC mode of the PDU session, e.g., the current PDU session Anchor and IP address. In an example, the SMF 160 may trigger e.g. new intermediate UPF 110 insertion or allocation of a new UPF 110. In an example, if the request type indicates emergency request, the SMF 160 may select the UPF 110 and may select SSC mode 1.

In an example, the SMF 160 may perform a session management policy modification procedure to report some event to the PCF 135 that has previously subscribed. If request type is initial request and dynamic PCC is deployed and PDU type is IPv4 or IPv6, the SMF 160 may notify the PCF 135 (that has previously subscribed) with the allocated UE 100 IP address/prefix.

In an example, the PCF 135 may provide updated policies to the SMF 160. The PCF 135 may provide authorized session-AMBR and the authorized 5QI and ARP to the SMF 160.

In an example, if request type indicates initial request, the SMF 160 may initiate an N4 session establishment procedure with the selected UPF 110. The SMF 160 may initiate an N4 session modification procedure with the selected UPF 110. In an example, the SMF 160 may send an N4 session establishment/modification request to the UPF 110 and may provide packet detection, enforcement, reporting rules, and/or the like to be installed on the UPF 110 for this PDU session. If CN tunnel info is allocated by the SMF 160, the CN tunnel info may be provided to the UPF 110. If the selective user plane deactivation is required for this PDU session, the SMF 160 may determine the Inactivity Timer and may provide it to the UPF 110. In an example, the UPF 110 may acknowledges by sending an N4 session establishment/modification response. If CN tunnel info is allocated by the UPF, the CN tunnel info may be provided to SMF 160. In an example, if multiple UPFs are selected for the PDU session, the SMF 160 may initiate an N4 session establishment/modification procedure with each UPF 110 of the PDU session.

In an example, the SMF 160 may send to the AMF 155 an Namf_Communication_N1N2MessageTransfer message (comprising PDU session ID, access type, N2 SM information (PDU session ID, QFI(s), QoS profile(s), CN tunnel info, S-NSSAI, session-AMBR, PDU session type, and/or the like), N1 SM container (PDU session establishment accept (QoS Rule(s), selected SSC mode, S-NSSAI, allocated IPv4 address, interface identifier, session-AMBR, selected PDU session type, and/or the like))). In case of multiple UPFs are used for the PDU session, the CN tunnel info may comprise tunnel information related with the UPF 110 that terminates N3. In an example, the N2 SM information may carry information that the AMF 155 may forward to the (R)AN 105 (e.g., the CN tunnel info corresponding to the core network address of the N3 tunnel corresponding to the PDU session, one or multiple QoS profiles and the corresponding QFIs may be provided to the (R)AN 105, the PDU session ID may be used by AN signaling with the UE 100 to indicate to the UE 100 the association between AN resources and a PDU session for the UE 100, and/or the like). In an example, a PDU session may be associated to an S-NSSAI and a DNN. In an example, the N1 SM container may contain the PDU session establishment accept that the AMF 155 may provide to the UE 100. In an example, multiple QoS rules and QoS profiles may be included in the PDU session establishment accept within the N1 SM and in the N2 SM information. In an example, the Namf_Communication_N1N2MessageTransfer may further comprise the PDU session ID and information allowing the AMF 155 to know which access towards the UE 100 to use.

In an example, the AMF 155 may send to the (R)AN 105 an N2 PDU session request (comprising N2 SM information, NAS message (PDU session ID, N1 SM container (PDU session establishment accept, and/or the like))). In an example, the AMF 155 may send the NAS message that may comprise PDU session ID and PDU session establishment accept targeted to the UE 100 and the N2 SM information received from the SMF 160 within the N2 PDU session request to the (R)AN 105.

In an example, the (R)AN 105 may issue AN specific signaling exchange with the UE 100 that may be related with the information received from SMF 160. In an example, in case of a 3GPP RAN 105, an RRC connection reconfiguration procedure may take place with the UE 100 to establish the necessary RAN 105 resources related to the QoS Rules for the PDU session request. In an example, (R)AN 105 may allocate (R)AN 105 N3 tunnel information for the PDU session. In case of dual connectivity, the master RAN 105 node may assign some (zero or more) QFIs to be setup to a master RAN 105 node and others to the secondary RAN 105 node. The AN tunnel info may comprise a tunnel endpoint for each involved RAN 105 node, and the QFIs assigned to each tunnel endpoint. A QFI may be assigned to either the master RAN 105 node or the secondary RAN 105 node. In an example, (R)AN 105 may forward the NAS message (PDU session ID, N1 SM container (PDU session establishment accept)) to the UE 100. The (R)AN 105 may provide the NAS message to the UE 100 if the necessary RAN 105 resources are established and the allocation of (R)AN 105 tunnel information are successful.

In an example, the N2 PDU session response may comprise a PDU session ID, cause, N2 SM information (PDU session ID, AN tunnel info, list of accepted/rejected QFI(s)), and/or the like. In an example, the AN tunnel info may correspond to the access network address of the N3 tunnel corresponding to the PDU session.

In an example, the AMF 155 may forward the N2 SM information received from (R)AN 105 to the SMF 160 via an Nsmf_PDUSession_UpdateSMContext request (comprising: N2 SM information, request type, and/or the like). In an example, if the list of rejected QFI(s) is included in N2 SM information, the SMF 160 may release the rejected QFI(s) associated QoS profiles.

In an example, the SMF 160 may initiate an N4 session modification procedure with the UPF 110. The SMF 160 may provide AN tunnel info to the UPF 110 as well as the corresponding forwarding rules. In an example, the UPF 110 may provide an N4 session modification response to the SMF 160.

In an example, the SMF 160 may send to the AMF 155 an Nsmf_PDUSession_UpdateSMContext response (Cause). In an example, the SMF 160 may subscribe to the UE 100 mobility event notification from the AMF 155 (e.g. location reporting, UE 100 moving into or out of area of interest), after this step by invoking Namf_EventExposure_Subscribe service operation. For LADN, the SMF 160 may subscribe to the UE 100 moving into or out of LADN service area event notification by providing the LADN DNN as an indicator for the area of interest. The AMF 155 may forward relevant events subscribed by the SMF 160.

In an example, the SMF 160 may send to the AMF 155, a Nsmf_PDUSession_SMContextStatusNotify (release). In an example, if during the procedure, any time the PDU session establishment is not successful, the SMF 160 may inform the AMF 155 by invoking an Nsmf_PDUSession_SMContextStatusNotify(release). The SMF 160 may releases any N4 session(s) created, any PDU session address if allocated (e.g. IP address) and may release the association with the PCF 135.

In an example, in case of PDU type IPv6, the SMF 160 may generate an IPv6 Router Advertisement and may send it to the UE 100 via N4 and the UPF 110.

In an example, if the PDU session may not be established, the SMF 160 may unsubscribe to the modifications of session management subscription data for the corresponding (SUPI, DNN, S-NSSAI), using Nudm_SDM_Unsubscribe (SUPI, DNN, S-NSSAI), if the SMF 160 is no more handling a PDU session of the UE 100 for this (DNN, S-NSSAI). In an example, if the PDU session may not be established, the SMF 160 may deregister for the given PDU session using Nudm_UECM_Deregistration (SUPI, DNN, PDU session ID).

The 5G system may support CIoT and/or MTC capabilities to support frequent small data transmission, infrequent small data transmission. The small data may comprise data payload in the range of e.g., 10, 20, 100 bytes or e.g., 1, 10, 20, 100(s) of kilo bytes.

In an example, CIoT features may support infrequent small data transmissions for at least low complexity, power constrained, low data rate CIoT UEs, and/or the like. In an example, the devices (e.g. utility meters, sensors, low power devices, and/or the like) may be mobile throughout their lifetime.

The end-to-end communications between the CIoT/MTC application in the UE and the CIoT/MTC application in the external network, may utilize services provided by the 3GPP system (e.g., 5GS). In an example, a capability server (e.g., a service capability server, SCS, and/or the like) may provide the end-to-end communications between the CIoT/MTC application in the UE and the CIoT/MTC application in the external network.

The CIoT/MTC application in the external network may be hosted by an application server (AS), an application function (AF) and/or the like. In an example, the AS and/or the AF may employ an SCS for additional value added services. The 3GPP system may provide transport, subscriber management and other communication services including various architectural enhancements, device triggering via control plane/user plane, data transmission via control plane/user plane, and/or the like.

In an example, device triggering may enable the capability server (e.g., SCS) to send information to the UE via the 3GPP network to trigger the UE to perform application specific actions. In an example, the application specific actions may comprise initiating communication with the SCS via the control plane, and/or user plane. Device triggering may be required when an IP address for the UE is not available or reachable by the SCS/AS, or AF.

A device trigger message may comprise information that may enable the network to route the message to the appropriate UE and the UE to route the message to the appropriate application. In an example, a trigger payload may comprise the information destined to the application, the information to route the information, and/or the like. In an example, the trigger payload, upon the reception by the UE may provide information to the application that may trigger application related actions. The application in the UE may perform indicated actions, such as for example to initiate immediate or later communication to the SCS/AS and/or AF, based on the information contained in the trigger payload.

In an example, device triggering may be subscription based. The subscription may provide the information whether a UE is allowed to be triggered by a specific SCS, SCS/AS, AF, and/or the like. In an example, when device triggers are delivered via MT-SMS the serving nodes (e.g., AMF, SMF, UPF, and/or the like) may provide the service towards a specific UE based on the UE's subscription for MT-SMS and other subscription parameters affecting MT-SMS service provision.

In an example, device triggering recall/replace functionality may allow a SCS, SCS/AS, or AF to recall or replace submitted trigger message(s) which are not yet delivered to the UE.

In an example, the 5GS may support functions for high latency communication, HLC. HLC may be used to handle mobile terminated (MT) communication with UEs being unreachable while using power saving functions e.g. UE power saving mode or extended idle mode DRX depending on operator configuration. High latency may be the initial response time before normal exchange of packets is established. The initial response time may be the time it takes before a UE has woken up from its power saving state and responded to the initial downlink packet(s).

In an example, high latency communication may be handled by an extended buffering of downlink data in a UPF, NEF, SMF, AMF, and/or the like. In an example, extended buffering may be controlled by the AMF, SMF, and/or the like. The AMF and/or the SMF may ask the UPF to buffer downlink data until the UE is expected to wake up from its power saving state.

In an example, if control plane CIoT optimization is used, high latency communication may be handled by the buffering of downlink data in the UPF, AMF, SMF and/or the like.

In an example, high latency communication may be handled by notification procedures. The SCS/AS or AF may request notification when a UE wakes up from its power saving state and sends downlink data to the UE when the UE is reachable. In an example, the notification procedure may be available based on monitoring event for UE reachability, monitoring event for availability after data notification (e.g., DDN) failure, and/or the like.

In an example, the SCS/AS or AF may request a one-time UE reachability notification when it wants to send data to the UE. In an example, the SCS/AS or AF may request repeated availability after DDN failure notifications where each notification is triggered by a DDN failure i.e. the SCS/AS may send a downlink packet which is discarded by a core network node (e.g., UPF, SMF, AMF) and may trigger the AMF or SMF to send an event notification to the SCS/AS next time the UE wakes up.

In an example, the length of the power saving intervals used by the network may determine the maximum latency for a UE. An SCS/AS or AF, which has a specific requirement on the maximum latency for UEs it communicates with, may provide its maximum latency requirement to the network.

In an example embodiment, a reachability procedure may be employed to reach a UE. Elements of the reachability procedure may be used by services such as SMS over NAS, data transmission for UEs in power saving mode, and/or the like. The reachability procedure may be employed by UEs that are in RRC-IDLE, RRC-INACTIVE or RRC-CONNECTED states.

In an example embodiment as depicted in example FIG. 14 , a UE reachability notification procedure may be employed.

In an example, during a registration or subscription update procedure, a UDM may inform an AMF of the identities (e.g. FQDNs, NF ID, and/or the like) of the network functions (NF) that are authorized to request notifications on the reachability of the UE via a registration service procedure such as Nudm_UECM_Registration, Nudm_SubscriberData_Update service operation, and/or the like.

In an example, if a service-related entity requests the UDM to provide an indication regarding UE reachability, the UDM may check that the service-related entity is authorized to perform this request on the subscriber associated to the UE. In an example, if the entity is not authorized, the request may be rejected (e.g. if the requesting entity is recognized as being a valid entity, but not authorized for that subscriber) or silently discarded (e.g. if the requesting entity is not recognized).

In an example, the UDM may store the identity of the service-related entity and may set the URRP-AMF parameter to indicate that such request is received. If the value of URRP-AMF parameter has changed from “not set” to “set”, the UDM may initiate Namf_EventExposure_Subscribe_service operation (URRP-AMF) towards the AMF. The UDM may indicate if direct notification to the NF may be used. In an example, the UDM may trigger UE reachability notification request procedure with two different AMFs for the UE which may be connected to 5G core network over 3GPP access and non-3GPP access simultaneously. In an example, the UDM may trigger UE reachability notification request procedure with a mobility management entity, MME.

In an example, the AMF may check that the requesting entity is authorized to perform the request on the subscriber. In an example, if the entity is not authorized, the request may be rejected (e.g. if the requesting entity is recognized as being a valid entity, but not authorized for the subscriber) or silently discarded (e.g. if the requesting entity is not recognized).

In an example, if the AMF has a MM Context for the user or the UE, the AMF may set URRP-AMF to indicate the need to report to the UDM information regarding changes in UE reachability, e.g. when the next NAS activity with that UE is detected.

In an example, if the UE state in the AMF is CM-CONNECTED state, the AMF may initiate N2 notification procedure with reporting type set to single RRC-Connected state notification.

In an example embodiment as depicted in example FIG. 15 , a UE activity notification procedure may be employed for reachability of a UE.

In an example, an AMF may receive an (N1) NAS signaling for a UE in CM-IDLE that may imply UE reachability, e.g. a registration request or service request message from the UE. In an example, AMF may receive an (N2) UE Notification or an (N2) Path Switch Request from the RAN for a UE in CM-CONNECTED state.

In an example, if the AMF has a MM context for the UE and the URRP-AMF is set to report once that the UE is reachable, the AMF may initiate a notification e.g., an Namf_EventExposure_Notify service operation (e.g., comprising SUPI, UE-Reachable, and/or the like) message to the UDM or directly to the NF (if previously indicated to the AMF). The AMF may clear the corresponding URRP-AMF for the UE.

In an example, when the UDM receives the Namf_EventExposure_Notify service operation (SUPI, UE-Reachable) message or Nudm_UECM_Registration service for a UE that has URRP-AMF set, the UDM may trigger appropriate notifications to the NFs (e.g. SMSF or SMS-GMSC, NEF, and/or the like) that have subscribed to the UDM for the reachability notification.

In an example embodiment, 5GS may support small data communication using an application programming interface (API) corresponding to e.g., T8 API, Nm API, and/or the like. The API may support packet transmission using IP-based, non-IP based, and/or the like protocols on the southbound interface. A messaging function entity (e.g., a network IoT messaging function, NIMF) may be employed. The NIMF may be an extension with an additional role for the 5G network exposure function (NEF), or it may be a new network function dedicated for small data communication for IoT/CIoT. In an example, the NIMF may be a new standalone network function entity.

The NIMF or NEF for small data communication may be located in the operator domain.

In an example, the NIMF may support a northbound Nm interface. On the northbound interface, the Small data network function may support for example the T8 non-IP data delivery NIDD Nm API, unstructured Nm API, and/or the like.

In an example, the NIMF may support a southbound N6m interface. The southbound interface may enable small data communication with different types of CIoT devices using different protocol stacks. In an example, the southbound interface has a PDU session layer which may support PDU Sessions of different types e.g., IPv4, IPv6, Ethernet, unstructured, non-IP, and/or the like. In an example, on top of the PDU session layer higher layer IoT protocols may be employed and supported towards the UE, e.g. Lightweight machine to machine, LWM2M, non-IP data delivery reliable data service, NIDD RDS, and/or the like.

The NIMF or NEF may store and forward small data. The southbound protocols may be terminated in the NIMF or NEF. The NIMF may map or act as proxies between the northbound and southbound protocols.

In an example, the NIMF may support lawful intercept LI (message based), charging (message based, i.e. number of CIoT messages), and/or the like.

In an example, if encryption protocols (e.g., datagram transport layer security (DTLS)) are employed as part of the southbound interface/connection, the NIMF may offer LI of unencrypted data.

In an example, when a UE establishes a PDU Session, as part of the registration procedure, or attach procedure, for which DNN configuration indicates small data communication to be used, then the SMF may initiate a connection towards the NEF or NIMF corresponding to the NEF ID or NIMF ID for the DNN.

In an example as depicted in example FIG. 16 , the UE may request the establishment of a PDU Session wherein an N4 session establishment in the UPF may be performed as part of the PDU session establishment.

In an example, a connection may be established between the UPF and the NIMF for the PDU Session. The NIMF may store the IP address of the PDU Session, the IMSI and the External ID or MSISDN of the UE, the IP version to use (IPv6, IPv4 or Unstructured), and PCO. In an example, for unstructured PDU session when point-to-point tunneling based on UDP/IP encapsulation is used, the UPF may store the forwarding IP address to the selected NIMF. For PDU sessions of type IP, the forwarding to the NIMF may be controlled by IP destination address used at the higher layer protocol (e.g., LWM2M).

In an example, uplink and downlink data transmissions may take place using IP data or Unstructured (Non-IP) data depending on the PDU Session type used by the UE.

In an example, when PDU Session release is initiated, the connection between the UPF and the NIMF may be released. The NIMF may remove the stored IP address of the PDU session, and may mark the UE as inactive, and may close the connection for (small) data transmissions to/from the UE. The N4 Session may be released in the UPF.

In an example embodiment as depicted in example FIG. 17 , the 5GS may support unstructured data transmission or non-IP data transmission (NIDD). The UE may support a NIDD client, for delivery of Unstructured (Non-IP) data. The SCS/AS or AF may send and receive messages to/from a given UE identified by an External Identifier, MSISDN, and/or the like. The UE may have an Unstructured PDU session activated and the message on the Nm or T8 API may be mapped to DL non-IP data PDU or from UL non-IP data PDU delivered to/from the UE. In an example, for the direct model case, the DL and UL data PDUs may be transmitted directly between the UPF and the SCS/AS.

In an example, an SCS/AS or AF may send a MT submit request with small data using T8 API, Nm API, and/or the like to a NEF or a NIMF.

The NIMF/NEF may determine the UE based on established connections and the external identifier or MSISDN included in the MT submit request. The NIMF may perform authorization and quota checks. If there is no established connection corresponding to the external identifier or MSISDN, the NIMF may send a MT submit response with appropriate error cause value. In an example, if there is no established connection corresponding to the external identifier or MSISDN, the NIMF/NEF may perform device triggering towards the UE to establish a connection.

The NIMF may sends a DL data PDU towards the UE using the IP address associated with the connection established by the UE. If the NIMF expects no acknowledgement on the message with the DL data PDU, the NIMF may sends a MT submit response to the SCS/AS informing that an unacknowledged transmission to the UE has been made.

In an example, the UE may send an UL data PDU to the NIMF. The NIMF may determine if the received UL data is an acknowledgement of the DL data. If the UL data PDU is an acknowledgement, the NIMF may send a MT Submit Response to the SCS/AS informing that an acknowledged transmission to the UE has been made.

In an example embodiment, a reliable data service (RDS) may be used by the UE and NEF for reliable (small) data delivery of unstructured PDU. The RDS may provide a mechanism for the NEF to determine if the data was successfully delivered to the UE and for the UE to determine if the data was successfully delivered to the NEF. In an example, when a requested acknowledgement is not received, the reliable data service may retransmit the packet. In an example, the RDS may employ NAS transport between the UE and the AMF for small data delivery. This may apply to both 3GPP and non-3GPP accesses. In an example, the RDS may require support for the AMF determining the NEF for a UE. In an example, the NEF may support subscription checking and actual transmission of MO/MT small data delivery by the NEF to the AF/UE. In an example, the RDS may support MO/MT small data delivery for both roaming and non-roaming scenarios, unstructured PDU, and/or API exposure for reliable data service towards 3rd party application providers.

In an example, during a registration procedure, a UE may provide RDS supported indication over NAS signaling indicating the UE's capability for support of RDS. In an example, the RDS supported indication may indicate whether the UE may support reliable small data delivery over NAS via 3GPP access or via both 3GPP and non-3GPP access. If the core network supports RDS functionality, the AMF may include RDS supported indication to the UE, and whether RDS delivery over NAS via 3GPP access or via both the 3GPP and non-3GPP access is accepted by the network.

In an example, RDS packets may be transmitted over NAS without the need to establish data radio bearers, via NAS transport message, which can carry RDS payload. PDU session establishment may not be needed. The UE and network may support RDS protocol. In an example, when the RDS is enabled, a protocol may be used between the end-points, e.g., between the UE and the NEF. The protocol may employ an RDS header to identify if the packet requires no acknowledgement, requires an acknowledgement, or is an acknowledgment and to allow detection and elimination of duplicate PDUs at the receiving endpoint. In an example, port numbers in the header may be used to identify the application on the originator and to identify the application on the receiver.

An example FIG. 18 depicts data transmission over NAS (e.g., MM-NAS and SM-NAS).

An example FIG. 19 depicts a reliable data service via control plane to an SCS/AS via an NEF. The scenarios depicted in FIG. 19 employ data transmission through AMF and through AMF and SMF.

An example FIG. 20 depicts data transmission via user plane from a wireless device to a data network and to a SCS/AS or an AF. The data transmission may employ an NEF network function with a data transmission support functionality.

An example FIG. 21 depicts an example of a network function registration with an NRF and configuration with an OAM. The network function may be a UPF as depicted in FIG. 21 . The network function may be an NEF, NIMF, and/or the like.

5GS may support (small) data transmission for cellular Internet of things (CIoT) applications. Data transmission may be via control plane and/or user plane (e.g. control plane network nodes and interfaces and/or user plane network nodes and interfaces). CIoT optimizations may require the network elements and network functions to support the CIoT data transmission functionality, CIoT enabling features, and/or the like. When a wireless requests to establish a PDU session to send data or packets to a SCS/AS or an AF, the wireless device may establish the PDU session via a NEF or an NIMF network function. The PDU session may employ the user plane network functions e.g., a UPF. If user plane data transmission is requested/selected, and a SMF an address of the NEF or the NIMF that serves a requested DNN and capable of CIoT data transmission, and/or a UPF that is capable of handling CIoT data transmission, the SMF may not be able to establish the PDU session and the PDU session establishment procedure may fail. The SMF may respond to the requesting network entity (e.g., an AMF) with an error cause message indicating a failure, PDU session establishment error, and/or the like and may stop the PDU session establishment procedure. An existing signaling mechanism for a PDU session establishment for CIoT data transmission may result in increased communication failures, an increased packet loss rate, a longer communication delay when data transmission associated with a CIoT functionality is initiated. Existing technologies for a PDU session establishment for a CIoT data transmission may cause inefficient signaling between network nodes and may degrade reliability of communication network systems.

Example embodiments provide reliable CIoT related services for a wireless device by enabling an SMF to select an NEF (and/or NIMF) based on a requested type of a PDU session and to get information of user plane network nodes (e.g. UPF, NEF, NIMF, and/or the like) supporting a CIoT data transmission from a network repository function (NRF). In an example, when receiving a data transmission request (e.g. small data transmission, CIoT data transmission), an SMF may request NEF, NIMF and/or UPF information to an NRF. In response to the NEF, NIMF, and/or UPF information request, the NRF may respond with an identifier and/or an address of a NEF, NIMF and/or UPF that supports a CIoT data transmission. Based on the identifier and/or the address of the NEF, NIMF and/or UPF, the SMF may send a connection establishment request to the NEF, NIMF, and/or the UPF. Example embodiments reduce a failure rate and/or a communication delay of a PDU session establishment procedure for CIoT data transmission by supporting a signaling mechanism for a SMF to get NEF, NIMF and/or UPF information for a CIoT service.

5GS may support (small) data transmission for cellular Internet of things (CIoT) applications. Data transmission may be via control plane and/or user plane (e.g. control plane network nodes and interfaces and/or user plane network nodes and interfaces). CIoT optimizations may require the network elements and network functions to support the CIoT data transmission functionality, CIoT enabling features, and/or the like. When a wireless device requests to establish a PDU session to send data or packets associated with CIoT applications to a SCS/AS or an AF, the wireless device may establish the PDU session via a NEF or an NIMF network function. The PDU session may employ the user plane network functions e.g., a UPF. If user plane data transmission is requested/selected, and a SMF does not have an address of the NEF or the NIMF that serves a requested DNN and capable of CIoT data transmission, and/or does not have an address of a UPF that is capable of CIoT data transmission, the SMF may not be able to establish the PDU session and the PDU session establishment procedure may fail. The SMF may respond to the requesting network entity (e.g., an AMF) with an error message indicating a failure, PDU session establishment error, and/or the like and may stop the PDU session establishment procedure. An existing signaling mechanism for a PDU session establishment for CIoT data transmission may result in increased communication failures, an increased packet loss rate, a longer communication delay when data transmission associated with a CIoT functionality is initiated. Existing technologies for a PDU session establishment for a CIoT data transmission may cause inefficient signaling between network nodes and may degrade reliability of communication network systems.

Example embodiments provide reliable CIoT related services for a wireless device by enabling an SMF to select an NEF (and/or NIMF) based on a requested type of a PDU session and to get information of user plane network nodes (e.g. UPF, NEF, NIMF, and/or the like) supporting a CIoT data transmission from a network repository function (NRF). In an example, when receiving a data transmission request (e.g. small data transmission, CIoT data transmission), an SMF may request NEF, NIMF and/or UPF information to an NRF. In response to the NEF, NIMF, and/or UPF information request, the NRF may respond with an identifier and/or an address of a NEF, NIMF and/or UPF that supports a CIoT data transmission. Based on the identifier and/or the address of the NEF, NIMF and/or UPF, the SMF may send a connection establishment request to the NEF, NIMF, and/or the UPF. Example embodiments reduce a failure rate and/or a communication delay of a PDU session establishment procedure for CIoT data transmission by supporting a signaling mechanism for a SMF to get NEF, NIMF and/or UPF information for a CIoT service.

When SMF receives the request to establish a PDU session to deliver IoT data from the UE, the preconfigured NEF or UPF may not (efficiently) support IoT data transmission to the UE. There is a need for discovery of an IoT capable NEF and/or UPF.

Implementation of signaling mechanism between SMF and NRF to discover an IoT capable NEF and/or UPF.

In an example embodiment, during the PDU session establishment procedure (e.g., depicted in FIG. 12 and FIG. 13 ), a wireless device, a UE, may send a NAS message to an AMF. The NAS message may comprise S-NSSAI(s), a DNN, a PDU session identifier (PDU session ID), a request type, an old PDU session identifier, an N1 SM container (e.g., comprising a PDU session establishment request), and/or the like. In an example, the PDU session establishment request may be a request for establishment of a PDU session for a cellular Internet-of-things (CIoT) packet transmission (CIoT packet transmission). In an example, in order to establish a new PDU session, the UE may generate a new PDU session identifier. In an example, the UE may initiate a UE requested PDU session establishment procedure by transmitting of a NAS message that may comprise a PDU session establishment request within the N1 SM container to request the PDU session. The PDU session establishment request may comprise a CIoT indicator, a PDU session identifier, a requested PDU type, a requested SSC mode, a 5G session management (5GSM) capability, protocol configuration options, an SM PDU DN request container, and/or the like. In an example, the CIoT indicator may be an information element indicating that the UE supports control plane CIoT optimizations, user plane CIoT optimizations, small data transmission for CIoT, and/or the like. In an example, the CIoT indicator may be an information element indicating that the PDU session establishment request may be for CIoT data transmission. In an example, the PDU session establishment request may further indicate that the PDU session is for a CIoT packet transmission. In an example, the PDU session type may indicate that the PDU session is for a CIoT packet transmission. In an example, the 5GSM capability may indicate UE's support for reflective QoS and for multi-homed IPv6 PDU session (e.g., if the requested PDU type was set to “IPv6” or “IPv4v6”). In an example, the PDU session establishment request message may comprise the SM PDU DN request container that may comprise information for PDU session authorization by an external DN. The UE may include an S-NSSAI from an allowed NSSAI of a current access type. If a mapping of the allowed NSSAI was provided to the UE, the UE may provide both the S-NSSAI from the allowed NSSAI and a corresponding S-NSSAI from the mapping of allowed NSSAI. In an example, the S-NSSAI may be associated with a CIoT service.

In an example, the AMF may determine that the NAS message may correspond to a request for a new PDU session if the request type indicates initial request and/or the PDU session identifier is not used for any existing PDU session(s) of the UE. If the NAS message does not contain an S-NSSAI, the AMF may determine a default S-NSSAI for the PDU session e.g., according to a subscription information of the UE, if the NAS message contains one default S-NSSAI, based on operator policy, and/or the like. In an example, the AMF may select an SMF. If the request type indicates existing PDU session, the AMF may select the SMF based on SMF-ID received from a UDM.

In an example, to select the SMF, the AMF may invoke a Nnssf_NSSelection_Get service operation from a network slice selection function (NSSF) in serving PLMN with the S-NSSAI (e.g., indicating that CIoT support may be required) from the allowed NSSAI requested by the UE, PLMN ID of the SUPI, TAI of the UE and may indicate that the request may be within a procedure of PDU session establishment in non-roaming, roaming with local breakout, PDU session establishment for CIoT, and/or the like. The NSSF in serving PLMN may select a network slice instance, and may determine and return an appropriate NRF (e.g., an identifier of NRF, an address of NRF, and/or the like). In an example, the network slice instance may support the CIoT data transmission. The appropriate NRF may be employed (e.g., by the AMF) to select network functions or network services within the selected network slice instance, and may return a network slice instance identifier corresponding to the network slice instance. In an example, the AMF may query the appropriate NRF in serving PLMN by issuing a Nnrf_NFDiscovery_Request comprising an S-NSSAI (e.g. the S-NSSAI from the wireless device and/or the default S-NSSAI) from the allowed NSSAI, PLMN ID of the SUPI, DNN, the CIoT indicator, an information element indicating that a CIoT service is required, the network slice instance identifier in case the AMF has stored the network slice instance identifier for the S-NSSAI from the allowed NSSAI, and/or the like. In an example, the NRF in serving PLMN may provide to the AMF, e.g. FQDN or IP address, of a set of discovered SMF instance(s) or endpoint address(es) of SMF service instance(s) in a Nnrf_NFDiscovery_Request response message, and/or the network slice instance identifier for a selected network slice instance corresponding to the S-NSSAI for subsequent NRF queries.

In an example embodiment as depicted in FIG. 22 and FIG. 23 , the SMF may receive from the AMF, a first message indicating the request for establishment of the PDU session for a cellular Internet-of-things (CIoT) packet transmission for the wireless device. The first message may comprise the DNN, a first single network slice selection assistance information (S-NSSAI) associated with the PDU session, an identifier of the PDU session (e.g., the PDU session ID), a PDU session type associated with the PDU session, an identifier of the wireless device, and/or the like. In an example, the first message may further comprise the CIoT indicator. In an example, the first message may indicate that a CIoT service is required.

In an example, the first message may be a PDU session create session management context request (e.g., an Nsmf_PDUSession_CreateSMContext request) (comprising a SUPI, the DNN, the first S-NSSAI, the PDU Session ID, AMF ID, request type, N1 SM container (e.g. PDU session establishment request), user location information, access type, PEI, GPSI, subscription for PDU session status notification, and/or the like), an Nsmf_PDUSession_UpdateSMContext Request (comprising the SUPI, the DNN, the first S-NSSAI, PDU session ID, AMF ID, request type, N1 SM container (PDU session establishment request), user location information, access type, RAT type, PEI, and/or the like), and/or the like.

In an example embodiment, the SMF may send to a network repository function (NRF) and in response to receiving the first message, at least one second message indicating a request for selection of a network exposure function (NEF/NIMF) for the CIoT packet transmission. In an example, the at least one second message may comprise the DNN, the first S-NSSAI associated with the PDU session, an identifier of the SMF, the PDU session type associated with the PDU session, and/or the like. In an example, the at least one second message may indicate a request for selection of a user plane function (UPF) for the CIoT packet transmission. In an example, the at least one second message may comprise an identifier of the SMF, a type of the UPF, the DNN, the first S-NSSAI associated with the PDU session, the PDU session type associated with the PDU session, and/or the like.

In an example embodiment, the SMF may send, to the NRF (or an OAM, a repository network element, network function, a user data management (UDM) and/or the like), the at least one second message indicating the request for selection of the NEF (or a network IoT messaging function, an NIMF), the request for selection of the UPF, and/or the like. In an example, the at least one second message may comprise at least one of an identifier of the SMF, the first S-NSSAI associated with the CIoT packet transmission, the PDU session type (e.g., unstructured, Ethernet, non-IP, IPv4, IPv6, and/or the like) associated with the CIoT packet transmission, the DNN, a UE identifier of the wireless device, and/or the like. The first S-NSSAI may indicate that a selection of a UPF network element may require an S-NSSAI consideration to support compatible network functionalities, e.g., slice type, slice description, slice isolation constraints, and/or the like.

In an example, the at least one second message may indicate that the request for selection of the NEF (NIMF) for the CIoT packet transmission or the request for selection of the UPF for the CIoT packet transmission, may initiate a network function discovery procedure. The network function discovery procedure may be to get information (e.g. an address and/or identifier) of the UPF, the NEF, the NIMF, a network element, and/or the like that supports transmission of packets for a CIoT service, small data transmission, CIoT optimization, and/or the like. The network function discovery procedure for the UPF, NEF, NIMF may comprise a discovery request message, a discovery request response message, and/or the like. The discovery request message may comprise an information element (IE) indicating that support of the CIoT packet transmission may be required by the UPF, NEF, NIMF, and/or the like. In an example, the at least one second message may be part of a network function (NF) discovery procedure or a NF service discovery procedure (e.g., a Nnrf_NFDiscovery service) via an NRF. In an example, the at least one second message may comprise at least one of a network function discovery message, and/or Nnrf_NFDiscovery_Request message. In an example, a NF (e.g. SMF) may send a discovery request message (e.g., the network function discovery message, Nnrf_NFDiscovery_Request, and/or the like) to the NRF and receive a discovery response message (e.g., Nnrf_NFDiscovery Response) from the NRF. The NF discovery procedure and/or NF service discovery procedure may enable a NF (e.g., the SMF) to discover a set of NF instance(s) with a NF service, a NF capability, a NF type, and/or the like.

In an example, in order to enable access to a requested NF type or NF service (e.g., the UPF, NIMF, and/or NEF supporting the NF type or the NF service), a requester NF (e.g., the SMF) may invoke the NF discovery procedure or the NF service discovery procedure by providing, to the NRF (e.g. via the at least one second message), a type of the NF or a specific service (e.g., service type), and/or other service parameters e.g., slicing related information to discover a NF. The requester (e.g. the SMF) may attempt to discover a network node (e.g. UPF, NEF, NIMF, and/or the like) supporting the type of the NF or the specific service. In an example, in response to receiving the at least one second message, the NRF may provide an IP address or a fully qualified domain name (FQDN) or an identifier of relevant services and/or NF instance(s) (e.g. an instance of the UPF, the NEF/NIMF, and/or the like) to the requester NF (e.g., the SMF) for NF selection. In an example, based on the received information (e.g., the IP address or the FQDN of the NF) from the NRF, the requester NF (e.g., the SMF) may select one or more NF instance(s) (e.g., an instance of the UPF, NEF, NIMF, and/or the like that may provide CIoT data transmission, device triggering, and/or the like) that may be able to provide the requested NF service(s).

In an example, the at least one second message may be a Nnrf_NFDiscovery_Request message. The Nnrf_NFDiscovery_Request message may comprise NF service name(s) (e.g., UPF, NEF, NIMF, user plane CIoT data transmission, CIoT/MTC data transmission, and/or the like), NF type of a target NF (e.g., the UPF, NEF/NIMF), a NF type of the NF service consumer (e.g., the SMF), S-NSSAI(s), an identifier of a target NF/NF service PLMN (e.g., UPF PLMN ID, NEF PLMN ID, NIMF PLMN ID, and/or the like), serving PLMN ID, an identifier of the service consumer NF (e.g., the SMF ID), and/or the like. In an example, in response to the at least one second message, the NRF may provide to the SMF, the IP address or FQDN of the expected NF instance(s) (e.g. the UPF, NEF, NIMF, and/or the like).

In an example, the network function discovery procedure and/or network function service discovery procedure may enable a network function (e.g., the SMF) to discover a set of network function instance(s) with a network function service, a network function capability, a network function type, and/or the like. In an example, the SMF may select the UPF network element locally or via the NRF by the network function discovery procedure. In an example, the SMF may select the UPF and/or the NEF/NIMF from a set of locally available candidate NFs (e.g., UPFs, NEFs, NIMFs, and/or the like) based on the elements of the first message, the CIoT indicator, the second S-NSSAI, the third S-NSSAI. In an example, the second S-NSSAI may be the first S-NSSAI, the third S-NSSAI or an S-NSSAI with the same or compatible service type or service description as the first S-NSSAI. In an example, the SMF may select the UPF, and/or the NEF/NIMF from a set of NF candidates received from the NRF (e.g., via the at least one third message). In an example, the set of candidate NFs may support CIoT (e.g., the CIoT packet transmission).

In an example, in response to receiving the at least one second messages, the NRF may select a network function (e.g. UPF, NEF, NIMF, and/or the like) supporting a CIoT functionality (e.g. a CIoT service, small data transmission, CIoT optimization, and/or the like). The NRF may be pre-configured with information of the network function supporting the CIoT functionality, and/or may receive information of the network function from an operations and management (OAM) network element. In an example, a network function (e.g. a UPF, an NEF, and/or an NIMF) may indicate to the NRF whether the network function supports the CIoT functionality. The NRF may select a network function (e.g. a UPF, an NEF, and/or an NIMF) supporting the CIoT functionality based on information pre-configured or received from an OAM and/or the network function.

In an example embodiment, the SMF may receive from the NRF and in response to the at least one second message, at least one third message. The at least one third message may comprise an address of the NEF, an identifier of the NEF, a third S-NSSAI that the NEF supported, and/or the like.

In an example embodiment, the at least one third message may comprise an address of the UPF (e.g., an IP address), an identifier of the UPF (e.g., UPF ID, UPF FQDN, and or the like), a second S-NSSAI that the UPF may support, and/or the like. In an example, the at least one third message may comprise an address of the NEF/NIMF (e.g., an IP address), an identifier of the NEF/NIMF (e.g., NEF ID, NEF FQDN, NIMF ID, NIMF FQDN, and or the like), a third S-NSSAI that the NEF/NIMF may support, and/or the like. In an example, the at least one third message may comprise the second S-NSSAI and/or the third S-NSSAI of the UPF and/or the NEF/NIMF. In an example, the second S-NSSAI and/or the third S-NSSAI, may indicate that the UPF and/or the NEF/NIMF belong to a network slice or a network slice instance that supports CIoT. In an example, the at least one third message may further comprise the CIoT indicator.

In an example embodiment, the SMF may send to the UPF, a fourth message indicating a connection establishment request with the NEF. In an example, the fourth message may comprise the identifier of the NEF (e.g., NIMF ID, NIMF FQDN, NEF ID, NEF FQDN, and or the like), the address of the NEF (e.g., an IP address), and/or the like. In an example, the fourth message may comprise an N4 session establishment/modification request message. In an example, when the N4 session establishment/modification request message indicates that the N4 session establishment/modification request is for a PDU session for a CIoT data transmission (e.g., over user plane) and the fourth message may comprise the identifier of the NEF/NIMF (e.g., the NEF ID, NEF FQDN, NIMF ID, NIMF FQDN, and or the like), the UPF may invoke a connection establishment procedure with the NEF/NIMF based on the elements of the fourth message. In an example, If the request type (e.g., the first message) indicates initial request, the SMF may initiate an N4 session establishment procedure with the selected UPF. In an example, the SMF may initiate an N4 session modification procedure with the selected UPF. In an example, the SMF may send an N4 session establishment/modification request to the UPF and may provide packet detection, enforcement and reporting rules to be installed on the UPF for the PDU session. If a core network CN tunnel info is allocated by the SMF, the CN tunnel info may be provided to the UPF. In an example, the NRF may provide a set of candidate NFs (e.g., UPFs, NEFs, NIMFs, and/or the like) to the SMF and the SMF may select the UPF, NEF/NIMF based on the received set of candidates NFs and the elements of the first message. In an example, the NRF may select the UPF, NEF, NIMF, and/or the like based on the elements of the second message. In an example, the SMF may select the UPF network element based on the elements of the first message and/or the fourth message.

If unstructured PDU type is supported by the UPF, the SMF may allocate an IPv6 prefix for the PDU session and for a point-to-point tunneling between the NEF/NIMF or a DN associated with the NEF/NIMF (e.g., N6 or N6m point-to-point tunneling). In an example, the point-to-point tunneling may be based on UDP/IP encapsulation. In an example, the UPF may map the addressing information (IP address, port number, and/or the like) between the UPF and the NEF/NIMF, or between the UPF and the DN, to a PDU session related information (e.g., the PDU session identifier). In an example, when point-to-point tunneling based on UDP/IPv6 is used, IPv6 prefix allocation for PDU sessions may be performed locally by a (H-)SMF. In an example, the UPF may act as a transparent forwarding node for payload between the UE and a destination node in the DN, e.g., for uplink, the UPF may forward unstructured PDU session type data to the destination node in the data network or the NEF/NIMF over a point-to-point tunnel (e.g., N6, N6m, and/or the like) using UDP/IPv6 encapsulation, or for downlink, the NEF/NIMF or the DN may send the unstructured PDU session type data using UDP/IPv6 encapsulation with an IPv6 address of the PDU session and a 3GPP defined UDP port for unstructured PDU session type data. The UPF acting as PDU session anchor may decapsulate (i.e. remove the UDP/IPv6 headers) received data (e.g., the one or more packets encapsulated with the IPv6 address of the PDU session) and may forward the received data identified by the IPv6 prefix of the PDU session for delivery to the UE.

In an example embodiment, the UPF may invoke a connection establishment procedure with the NEF/NIMF. The connection establishment procedure may comprise a connection establishment request message, a session establishment request message, an association request message and/or the like. In an example, the connection establishment request message, the session establishment request message or the association request message may comprise the identifier of the PDU session, the PDU session type associated with the PDU session, the identifier and/or address of the UPF, the identifier and/or address the SMF, and/or the like. When a connection is established between the UPF and the NEF/NIMF for the PDU session, the NEF/NIMF may store an IP address of the PDU session, the IMSI and the external ID or MSISDN of the UE, the IP version to use (IPv6, IPv4 or Unstructured), protocol configuration options PCO, and/or the like. In an example, for unstructured PDU session, when point-to-point tunneling based on UDP/IP encapsulation is used, the UPF may store the forwarding IP address to the selected NEF/NIMF. For PDU sessions of type IP, forwarding to the NIMF may be controlled by IP destination address used at application layer protocol, and/or the like.

In an example, upon successful connection establishment procedure with the NEF/NIMF and/or establishment of the PDU session for CIoT, the UPF may transmit data (e.g., CIoT small data, packets, and/or the like) to the NEF/NIMF to be delivered to a SCS/AS and/or an AF. The data may be encapsulated and transmitted via the point-to-point tunneling based on UDP/IP encapsulation. In an example, the UPF interaction with the NEF/NIMF may be a service based interaction. The service based interaction may comprise sending by the UPF to the NEF/NIMF a data transmission request message to the NEF/NIMF (e.g., a data transfer service request). The data transmission request may comprise the NEF/NIMF ID, an address/identifier of an AS, an address/identifier of a SCS/AS, an address/identifier of an AF, the data (e.g., data packets, small data, and/or the like), type of request, and/or the like. In an example, the NEF/NIMF may interact with the SCS/AS, or AF via an application programming interface (API). In an example, the API (e.g., a northbound API) may be an interface between the AS, SCS/AS, and/or AF, (e.g., either in a mobile operator's network or external to it—operated by a third party) and the 3GPP system via specified functions in a mobile operator's network. In an example, APIs may enable interaction at the application layer. In an example, support of data communication (e.g., CIoT data transmission, or small data transmission) using an API may correspond to a T8 API (e.g., the API between the SCS/AS and a SCEF), an API between the NEF/NIMF and the SCS/AS, an API between the NEF/NIMF and the AF, and/or the like. In an example, the NEF/NIMF may support an API (e.g., Nm API) and may support transmission using IP-based, non-IP based, unstructured, Ethernet, and/or the like protocols on a southbound interface towards the 3GPP network. In an example, the NIMF may be an extension with an additional role for a 5G network exposure function (NEF), or it may be a new network function dedicated for CIoT data transmission, or small data communication, or it may be a standalone network function/entity. In an example, the UPF may receive the data via control plane (e.g., the SMF) or the user plane (e.g., via a RAN, a 3GPP access point, a non-3gpp access point, and/or the like).

In an example, the first S-NSSAI, the second S-NSSAI, and the third S-NSSAI may be the same and/or compatible (e.g., same slice type, slice descriptor and/or the like).

In an example embodiment as depicted in FIG. 24 and FIG. 25 , a UPF may receive from an SMF, a first message indicating a request for establishment of a PDU session for a CIoT packet transmission. The first message may comprise a PDU session type associated with the PDU session, a data network name (DNN), a first single network slice selection assistance information (S-NSSAI) associated with the PDU session, a packet forwarding indication, an identifier of the PDU session, an identifier of a wireless device, the CIoT indicator, and/or the like. In an example, the first message may be an N4 session establishment/modification request. In an example, when the N4 session establishment/modification request indicates that the N4 session establishment/modification request is for a PDU session for a CIoT data transmission (e.g., over user plane) and determines that an NEF and/or an NIMF discovery is required, the UPF may query the NRF with a discovery request message as part of a network function discovery procedure. In an example, the N4 session establishment/modification request to the UPF may comprise packet detection, enforcement and reporting rules to be installed on the UPF for the PDU session.

In an example embodiment, the UPF may send to the NRF, a second message indicating a request for selection of a network exposure function (NEF/NIMF) for the CIoT packet transmission. In an example, the second message may comprise the DNN, the first S-NSSAI associated with the PDU session, the PDU session type associated with the PDU session, an identifier of the UPF, a type of the NEF, and/or the like. In an example, the second message may be the discovery request message as part of the service discovery procedure or the network discovery procedure. In an example, the UPF may send to a network repository function (NRF) the second message indicating a request for selection of an NEF/NIMF for the CIoT packet transmission. In an example, the second message may comprise the DNN, the first S-NSSAI associated with the PDU session, an identifier of the UPF, the PDU session type associated with the PDU session, and/or the like. In an example, the second message may indicate a request for selection of a user plane function NEF/NIMF for the CIoT packet transmission. In an example, the at least one second message may comprise an identifier of the UPF, a type of the NEF/NIMF, the DNN, the first S-NSSAI associated with the PDU session, the PDU session type associated with the PDU session, and/or the like.

In an example embodiment, the UPF may send, to the NRF (or an OAM, a repository network element, network function, a user data management (UDM) and/or the like), the second message indicating the request for selection of the NEF (or a network IoT messaging function, an NIMF). In an example, the second message may comprise at least one of an identifier of the UPF, the first S-NSSAI associated with the CIoT packet transmission, the PDU session type (e.g., unstructured, Ethernet, non-IP, IPv4, IPv6, and/or the like) associated with the CIoT packet transmission, the DNN, a UE identifier of the wireless device, and/or the like. The first S-NSSAI may indicate that a selection of a UPF network element may require an S-NSSAI consideration to support compatible network functionalities, e.g., slice type, slice description, slice isolation constraints, and/or the like.

In an example, the second message may indicate that the request for selection of the NEF (NIMF) for the CIoT packet, may initiate a network function discovery procedure. The network function discovery procedure may be to get information (e.g. an address and/or identifier) of the NEF, the NIMF, a network element, and/or the like that supports transmission of packets for a CIoT service, small data transmission, CIoT optimization, and/or the like. The network function discovery procedure for the NEF, NIMF may comprise a discovery request message, a discovery request response message, and/or the like. The discovery request message may comprise an information element (IE) indicating that support of the CIoT packet transmission may be required by the NEF, NIMF, and/or the like. In an example, the second message may be part of a network function (NF) discovery procedure or a NF service discovery procedure (e.g., a Nnrf_NFDiscovery service) via an NRF. In an example, the second message may comprise at least one of a network function discovery message, and/or Nnrf_NFDiscovery_Request message. In an example, a NF (e.g. UPF) may send a discovery request message (e.g., the network function discovery message, Nnrf_NFDiscovery_Request, and/or the like) to the NRF and receive a discovery response message (e.g., Nnrf_NFDiscovery Response) from the NRF. The NF discovery procedure and/or NF service discovery procedure may enable a NF (e.g., the SMF) to discover a set of NF instance(s) with a NF service, a NF capability, a NF type, and/or the like.

In an example, in order to enable access to a requested NF type or NF service (e.g., the NIMF, and/or NEF supporting the NF type or the NF service), a requester NF (e.g., the UPF) may invoke the NF discovery procedure or the NF service discovery procedure by providing, to the NRF (e.g. via the second message), a type of the NF or a specific service (e.g., service type), and/or other service parameters e.g., slicing related information to discover a NF. The requester (e.g. the UPF) may attempt to discover a network node (e.g. NEF, NIMF, and/or the like) supporting the type of the NF or the specific service. In an example, in response to receiving the second message, the NRF may provide an IP address or a fully qualified domain name (FQDN) or an identifier of relevant services and/or NF instance(s) (e.g. an instance of the UPF, the NEF/NIMF, and/or the like) to the requester NF (e.g., the SMF) for NF selection. In an example, based on the received information (e.g., the IP address or the FQDN of the NF) from the NRF, the requester NF (e.g., the SMF) may select one or more NF instance(s) (e.g., an instance of the UPF, NEF, NIMF, and/or the like that may provide CIoT data transmission, device triggering, and/or the like) that may be able to provide the requested NF service(s).

In an example, the second message may be a Nnrf_NFDiscovery_Request message. The Nnrf_NFDiscovery_Request message may comprise NF service name(s) (e.g., NEF, NIMF, user plane CIoT data transmission, CIoT/MTC data transmission, and/or the like), NF type of a target NF (e.g., the NEF/NIMF), a NF type of the NF service consumer (e.g., the UPF), S-NSSAI(s), an identifier of a target NF/NF service PLMN (e.g., NEF PLMN ID, NIMF PLMN ID, and/or the like), serving PLMN ID, an identifier of the service consumer NF (e.g., the UPF ID), and/or the like. In an example, in response to the second message, the NRF may provide to the UPF, the IP address or FQDN of the expected NF instance(s) (e.g. the NEF, NIMF, and/or the like).

In an example, the network function discovery procedure and/or network function service discovery procedure may enable a network function (e.g., the UPF) to discover a set of network function instance(s) with a network function service, a network function capability, a network function type, and/or the like. In an example, the UPF may select the NEF/NIMF locally or via the NRF by the network function discovery procedure. In an example, the UPF may select the NEF/NIMF from a set of locally available candidate NFs (e.g., NEFs, NIMFs, and/or the like) based on the elements of the first message, the CIoT indicator, the first S-NSSAI, and/or the second S-NSSAI. In an example, the second S-NSSAI may be the first S-NSSAI or an S-NSSAI with the same or compatible service type or service description as the first S-NSSAI. In an example, the UPF may select the NEF/NIMF, from a set of NF candidates received from the NRF (e.g., via the at least one third message). In an example, the set of candidate NFs may support CIoT (e.g., the CIoT packet transmission).

In an example, in response to receiving the second messages, the NRF may select a network function (e.g. NEF, NIMF, and/or the like) supporting a CIoT functionality (e.g. a CIoT service, small data transmission, CIoT optimization, and/or the like). The NRF may be pre-configured with information of the network function supporting the CIoT functionality, and/or may receive information of the network function from an operations and management (OAM) network element. In an example, a network function (e.g. a UPF, an NEF, and/or an NIMF) may indicate to the NRF whether the network function supports the CIoT functionality. The NRF may select a network function (e.g. a UPF, an NEF, and/or an NIMF) supporting the CIoT functionality based on information pre-configured or received from an OAM and/or the network function.

In an example embodiment, in response to the discovery request message (e.g., the second message), the UPF may receive from the NRF a third message. The third message may comprise an identifier of the NEF/NIMF (e.g., FQDN), an address of the NEF/NIMF (e.g., an IP address), a second S-NSSAI that the NEF/NIMF may support, and/or the like. In an example, the third message may be the discovery response message as part of the service discovery procedure or the network discovery procedure. In an example, the third message may be part of a network function (NF) discovery procedure or a NF service discovery procedure (e.g., a Nnrf_NFDiscovery service) via an NRF. In an example, the third message may comprise at least one of a network function discovery message, and/or Nnrf_NFDiscovery_Request message. In an example, a NF (e.g. the UPF) may send a discovery request message (e.g., the network function discovery message, Nnrf_NFDiscovery_Request, and/or the like) to the NRF and receive a discovery response message (e.g., Nnrf_NFDiscovery Response) from the NRF. The NF discovery procedure and/or NF service discovery procedure may enable a NF (e.g., the UPF) to discover a set of NF instance(s) with a NF service, a NF capability, a NF type, and/or the like.

In an example, in order to enable access to a requested NF type or NF service (e.g., the NIMF, and/or NEF supporting the NF type or the NF service), a requester NF (e.g., the UPF) may invoke the NF discovery procedure or the NF service discovery procedure by providing, to the NRF (e.g. via the at least one second message), a type of the NF or a specific service (e.g., service type), and/or other service parameters e.g., slicing related information to discover a NF. The requester (e.g. the UPF) may attempt to discover a network node (e.g. NEF, NIMF, and/or the like) supporting the type of the NF or the specific service. In an example, in response to receiving the first message, the NRF may provide an IP address or a fully qualified domain name (FQDN) or an identifier of relevant services and/or NF instance(s) (e.g. an instance of the NEF/NIMF, and/or the like) to the requester NF (e.g., the UPF) for NF selection. In an example, based on the received information (e.g., the IP address or the FQDN of the NF) from the NRF, the requester NF (e.g., the UPF) may select one or more NF instance(s) (e.g., an instance of the NEF, NIMF, and/or the like that may provide CIoT data transmission, device triggering, and/or the like) that may be able to provide the requested NF service(s).

In an example, the at least one second message may be a Nnrf_NFDiscovery_Request message. The Nnrf_NFDiscovery_Request message may comprise NF service name(s) (e.g., NEF, NIMF, user plane CIoT data transmission, CIoT/MTC data transmission, and/or the like), NF type of a target NF (e.g., the NEF/NIMF), a NF type of the NF service consumer (e.g., the UPF), S-NSSAI(s), an identifier of a target NF/NF service PLMN (e.g., NEF PLMN ID, NIMF PLMN ID, and/or the like), serving PLMN ID, an identifier of the service consumer NF (e.g., the UPF ID), and/or the like. In an example, in response to the first message, the NRF may provide to the UPF, the IP address or FQDN of the expected NF instance(s) (e.g. the NEF, NIMF, and/or the like). In an example the NRF may select the requested network function and return the selected NF via a network discovery response message.

In an example embodiment, the UPF may send to the NEF/NIMF, a fourth message indicating a connection establishment request with the NEF/NIMF. The fifth message may comprise the identifier of the PDU session, the PDU session type associated with the PDU session.

In an example, the first S-NSSAI may be the second S-NSSAI.

In an example embodiment as depicted in FIG. 21 , when a new network function/network element (e.g., UPF, NEF, NIMF, and/or the like) is instantiated or deployed, the new network function may register itself with the NRF or an OAM. The new network function (e.g., the UPF, the NEF, the NIMF) may send a registration message indicating that the new network function may support the CIoT packet transmission, small data transmission, CIoT optimization, CIoT indicator, and/or the like. In an example, the registration message may comprise at least one of a network function profile of the UPF, NEF, or NIMF, an identifier of the UPF, NEF, or NIMF, an S-NSSAI that the new network function may support, a DNN associated with the new network function, and/or the like. In an example, the NRF may be configured by an OAM with information on available UPF(s), NEF(s), NIMF(s). In an example, the registration message may comprise an information element indicating that user plane CIoT optimization, user plane CIoT packet transmission, small data transmission, the CIoT optimization, and/or the like may be supported by the new network function. In an example, the registration message may further comprise an identifier of the UPF/NEF/NIMF, a capability information of the UPF/NEF/NIMF, a traffic routing capability of the UPF/NEF/NIMF, a network function type of the UPF/NEF/NIMF, an IP address (e.g., IPv4, and/or IPv6) of the UPF/NEF/NIMF, a fully qualified domain name (FQDN) of the UPF/NEF/NIMF, a profile of the UPF/NEF/NIMF, a list of supported S-NSSAIs associated with the UPF/NEF/NIMF, and/or the like. In an example, the profile of the UPF/NEF/NIMF may be employed to describe the characteristics of a UPF/NEF/NIMF instance. When an UPF/NEF/NIMF network function instance is instantiated, the associated UPF/NEF/NIMF network function profile may be generated and stored on the UPF/NEF/NIMF network function instance. During a service registration procedure, the UPF/NEF/NIMF network function profile may be registered and stored on the NRF. The profile of the UPF/NEF/NIMF network function may comprise a type of the UPF/NEF/NIMF network function, an FQDN and/or IP address of the UPF/NEF/NIMF network function instance, network slice related identifier(s) e.g. S-NSSAI, network slice instance identifier (NSI ID), UPF/NEF/NIMF network function capacity information, permissions, authorization information, and/or the like.

In an example embodiment, a session management function (SMF) may receive from an access and mobility management function (AMF), a first message indicating a request for establishment of a PDU session for a cellular Internet-of-things (CIoT) packet transmission of a wireless device. The first message may comprise a data network name (DNN), a first single network slice selection assistance information (S-NSSAI) associated with the PDU session, and/or the like.

In an example embodiment, the SMF may send to a network repository function (NRF) and in response to receiving the first message, at least one second message indicating a request for selection of a network exposure function (NEF/NIMF) for the CIoT packet transmission. The at least one second message may comprise the DNN, the first S-NSSAI associated with the PDU session, and/or the like.

In an example embodiment, the SMF may receive from the NRF and in response to the at least one second message, at least one third message. The at least one third message may comprise an address of the NEF, an identifier of the NEF, and/or the like.

In an example embodiment, the SMF may send to a user plane function (UPF), a fourth message indicating a connection establishment request with the NEF. The fourth message may comprise the identifier of the NEF, the address of the NEF, and/or the like.

In an example embodiment, the first message may further comprise at least one of an identifier of the PDU session, a PDU session type associated with the PDU session, an identifier of the wireless device, and/or the like.

In an example embodiment, the at least one second message may further indicate a request for selection of a UPF for the CIoT packet transmission. The at least one second message may further comprise at least one of an identifier of the SMF, a type of the UPF, the DNN, the first S-NSSAI associated with the PDU session, the PDU session type associated with the PDU session, and/or the like.

In an example embodiment, the at least one third message may further comprise a third S-NSSAI that the NEF may support.

In an example embodiment, the at least one third message may further comprise at least one of an identifier of the UPF, an address of the UPF, a second S-NSSAI that the UPF may support, and/or the like.

In an example embodiment, the fourth message may further comprise the identifier of the PDU session.

In an example embodiment, the first S-NSSAI may be the second S-NSSAI. In an example embodiment, the first S-NSSAI may be the third S-NSSAI.

In an example embodiment, a user plane function (UPF) may receive from a session management function (SMF), a first message indicating a request for establishment of a PDU session for a cellular Internet-of-things (CIoT) packet transmission. The first message may comprise a PDU session type associated with the PDU session, a data network name (DNN), a first single network slice selection assistance information (S-NSSAI) associated with the PDU session, and/or the like.

In an example embodiment, the UPF may send to a network repository function (NRF), a second message indicating a request for selection of a network exposure function (NEF/NIMF) for the CIoT packet transmission. The second message may comprise the DNN, the first S-NSSAI associated with the PDU session, the PDU session type associated with the PDU session, and/or the like.

In an example embodiment, the UPF may receive from the NRF and in response to the second message, a third message. The third message may comprise an identifier of the NEF, an address of the NEF, a second S-NSSAI that the NEF supports, and/or the like.

In an example embodiment, the UPF may send to the NEF, a fourth message indicating a connection establishment request with the NEF. The fifth message may comprise the identifier of the PDU session, the PDU session type associated with the PDU session, and/or the like.

In an example embodiment, the first message may further comprise at least one of a packet forwarding indication, an identifier of the PDU session, an identifier of a wireless device, and/or the like.

In an example embodiment, the second message may further comprise at least one of an identifier of the UPF, a type of the NEF, and/or the like.

In an example embodiment, the first S-NSSAI may be the second S-NSSAI.

According to various embodiments, a device such as, for example, a wireless device, off-network wireless device, a base station, and/or the like, may comprise one or more processors and memory. The memory may store instructions that, when executed by the one or more processors, cause the device to perform a series of actions. Embodiments of example actions are illustrated in the accompanying figures and specification. Features from various embodiments may be combined to create yet further embodiments.

FIG. 30 is an example flow diagram as per an aspect of an embodiment of the present disclosure. At 3010, a session management function (SMF) may receive a first message from an access and mobility management function (AMF). The first message may request establishment of a packet data unit (PDU) session for transmission of Internet-of-things (IoT) data from a wireless device. At 3020, the SMF may determine that the PDU session for transmission of the IoT data requires a network exposure function that supports IoT data transmission. At 3030, the SMF may send a second message to a network repository function based on the determining (3020). The second message may request discovery of the network exposure function. The second message may comprise a parameter indicating the IoT data transmission. At 3040, the SMF may receive a third message from the network repository function based on the parameter. The third message may comprise an identifier of the network exposure function that supports the IoT data transmission. At 3050, the SMF may send a fourth message to a user plane function. The fourth message may request establishment of a connection for the PDU session with the network exposure function for transmission of the IoT data from the wireless device. The fourth message may comprise the identifier of the network exposure function.

According to an example embodiment, the IoT data may be cellular IoT (CIoT) data. According to an example embodiment, the SMF may select the user plane function based on the user plane function supporting CIoT data transmission. According to an example embodiment, the session may be an N4 session. According to an example embodiment, the SMF may select the user plane function. According to an example embodiment, the SMF may send a session establishment request to the user plane function. The session establishment request may comprise an identifier of a session. According to an example embodiment, the SMF may receive a session establishment response from the user plane function.

According to an example embodiment, the first message may comprise a data network name (DNN). According to an example embodiment, the first message may comprise a single network slice selection assistance information (S-NSSAI) associated with the PDU session. According to an example embodiment, the first message may comprise an identifier of the PDU session. According to an example embodiment, the first message may comprise a PDU session type associated with the PDU session. According to an example embodiment, the first message may comprise an identifier of the wireless device. According to an example embodiment, the second message may comprise a data network name (DNN). According to an example embodiment, the second message may comprise a single network slice selection assistance information (S-NSSAI) associated with the PDU session. According to an example embodiment, the second message may comprise an S-NSSAI associated with the session management function. According to an example embodiment, the second message may comprise a request to discover a user plane function that supports the transmission of the IoT data.

According to an example embodiment, the third message may comprise an address of the network exposure function. According to an example embodiment, the third message may comprise an identifier of the user plane function that supports the transmission of the IoT data.

According to an example embodiment, the user plane function may send to the network exposure function, a request to establish a connection with the network exposure function. According to an example embodiment, the request to establish the connection with the network exposure function may comprise an identifier of an application function.

According to an example embodiment, the user plane function may receive one or more packets from the wireless device. According to an example embodiment, the user plane function may receive the one or more packets from the wireless device via the session management function. According to an example embodiment, the user plane function may receive the one or more packets from the wireless device via a base station. According to an example embodiment, the user plane function may send to the network exposure function, the one or more packets destined to an application function. According to an example embodiment, the network exposure function may send the one or more packets to the application function.

FIG. 31 is an example flow diagram as per an aspect of an embodiment of the present disclosure. According to an example embodiment, at 3110, the network repository function may send a request to an operation and management (OAM) network element. The request may be to discover the network exposure function that supports the transmission of the IoT data. According to an example embodiment, the action of 3110 may occur after 3060. According to an example embodiment, at 3110, the network repository function may receive an identifier of the network exposure function that supports the transmission of the IoT data from the OAM network element. The identifier.

FIG. 32 is an example flow diagram as per an aspect of an embodiment of the present disclosure. At 3210, a user plane function may receive a first message from a session management function (SMF). The first message may request establishment of a packet data unit (PDU) session for transmission of Internet-of-things (IoT) data from a wireless device. At 3220, the user plane function may determine that the PDU session for transmission of the IoT data requires a network exposure function that supports IoT data transmission. At 3230, based on the determining, the user plane function may send a second message to a network repository function. The second message may request discovery of the network exposure function, the second message may comprise a parameter indicating the IoT data transmission. At 3240, the user plane function may receive a third message from the network repository function based on the parameter. The third message may comprise an identifier of the network exposure function that supports the IoT data transmission. At 3250, the user plane function may send a fourth message to the network exposure function. The fourth message may request establishment of a connection for the PDU session with the network exposure function for transmission of the IoT data from the wireless device. The fourth message may comprise the identifier of the PDU session.

FIG. 33 illustrates an example flow diagram(s) as per aspect(s) of embodiment(s) of the present disclosure. According to an example embodiment, the IoT may be cellular IoT (CIoT). According to an example embodiment, at 3310, the SMF may select the user plane function that supports the CIoT data transmission. According to an example embodiment, the action of 3310 may occur after 3260. According to an example embodiment, at 3320, the network repository function may send a request to an operation and management (OAM) network element. The request may be to discover the network exposure function that supports transmission of the IoT data. According to an example embodiment, the action of 3320 may occur after 3260. According to an example embodiment, at 3330, the network repository function may receive the identifier of the network exposure function that supports the transmission of the IoT data from the OAM network element.

According to an example embodiment, the SMF, may select the user plane function. According to an example embodiment, the user plane function may receive from the SMF, a session establishment request may comprise an identifier of a session. According to an example embodiment, the user plane function may send a session establishment response to the SMF. According to an example embodiment, the session is an N4 session.

According to an example embodiment, the first message may comprise a data network name (DNN). According to an example embodiment, the first message may comprise a single network slice selection assistance information (S-NSSAI) associated with the PDU session. According to an example embodiment, the second message may comprise a data network name (DNN). According to an example embodiment, the second message may comprise a single network slice selection assistance information (S-NSSAI) associated with the PDU session. According to an example embodiment, the second message may comprise a S-NSSAI associated with the user plane function. According to an example embodiment, the third message may comprise an address of the network exposure function.

According to an example embodiment, the user plane function may send to the network exposure function, a request to establish a connection with the network exposure function. According to an example embodiment, the request to establish the connection with the network exposure function may comprise an identifier of an application function. According to an example embodiment, the user plane function may receive one or more packets from the wireless device. According to an example embodiment, the user plane function may receive the one or more packets from the wireless device via the session management function. According to an example embodiment, the user plane function may receive the one or more packets from the wireless device via a base station. According to an example embodiment, the user plane function may send to the network exposure function, the one or more packets destined to an application function. According to an example embodiment, the network exposure function may send the one or more packets to the application function. According to an example embodiment, the session management function may receive from an access and mobility management function (AMF), a message requesting establishment of the packet data unit (PDU) session for transmission of the IoT data from the wireless device.

In this specification, a and an and similar phrases are to be interpreted as at least one and one or more. In this specification, the term may is to be interpreted as may, for example. In other words, the term may is indicative that the phrase following the term may is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. If A and B are sets and every element of A is also an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B={cell1, cell2} are: {cell1}, {cell2}, and {cell1, cell2}.

In this specification, parameters (Information elements: IEs) may comprise one or more objects, and each of those objects may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J, then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more messages comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages, but does not have to be in each of the one or more messages.

Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an isolatable element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (i.e. hardware with a biological element) or a combination thereof, which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling/simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. Additionally, it may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and/or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers and microprocessors are programmed using languages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. Finally, it needs to be emphasized that the above mentioned technologies are often employed in combination to achieve the result of a functional module.

Example embodiments of the invention may be implemented using various physical and/or virtual network elements, software defined networking, virtual network functions.

The disclosure of this patent document incorporates material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, for the limited purposes required by law, but otherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made therein without departing from the spirit and scope. In fact, after reading the above description, it will be apparent to one skilled in the relevant art(s) how to implement alternative embodiments. Thus, the present embodiments should not be limited by any of the above described exemplary embodiments. In particular, it should be noted that, for example purposes, the above explanation has focused on the example(s) using 5G AN. However, one skilled in the art will recognize that embodiments of the invention may also be implemented in a system comprising one or more legacy systems or LTE. The disclosed methods and systems may be implemented in wireless or wireline systems. The features of various embodiments presented in this invention may be combined. One or many features (method or system) of one embodiment may be implemented in other embodiments. A limited number of example combinations are shown to indicate to one skilled in the art the possibility of features that may be combined in various embodiments to create enhanced transmission and reception systems and methods.

In addition, it should be understood that any figures which highlight the functionality and advantages, are presented for example purposes. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the actions listed in any flowchart may be re-ordered or optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The Abstract of the Disclosure is not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include the express language means for or step for be interpreted under 35 U.S.C. 112. Claims that do not expressly include the phrase means for or step for are not to be interpreted under 35 U.S.C. 112. 

What is claimed is:
 1. A method, comprising: receiving, by an access and mobility management function (AMF) from a wireless device, a first request to establish a session; sending, by the AMF to a network repository function (NRF), a second request requesting discovery of a session management function (SMF), wherein the second request includes a cellular internet of things (CIoT) indication; receiving, by the AMF from the NRF, an identifier of the SMF that supports CIoT optimization; and sending, by the AMF to the SMF, a third request to establish the session for CIoT packet transmission.
 2. The method of claim 1, wherein the third request comprises: a data network name (DNN); a single network slice selection assistance information (S-NSSAI) associated with the session; an identifier of the session; a session type associated with the session; and an identifier of the wireless device.
 3. The method of claim 1, wherein the session is a packet data unit (PDU) session, and wherein the CIoT indication is a control plane CIoT optimization indication.
 4. The method of claim 1, wherein the CIoT indication is a CIoT optimization indication.
 5. The method of claim 1, wherein the first request comprises the CIoT indication.
 6. The method of claim 5, wherein the SMF supports exchange of user data of the wireless device between the wireless device and the SMF using a non-access stratum message, and wherein the exchange of the user data comprises transmission of the user data over a control plane.
 7. The method of claim 1, further comprising sending, by the AMF to a network slice selection function (NSSF), a slice selection request indicating that a slice is for the session.
 8. The method of claim 7, further comprising, receiving by the AMF from the NSSF, an address of the NRF.
 9. The method of claim 1, wherein the first request comprises an identifier of the session.
 10. The method of claim 1, wherein the session is a packet data unit (PDU) session, and wherein the first request comprises a PDU session type associated with the PDU session.
 11. An access and mobility management function (AMF), comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the AMF to: receive, from a wireless device, a first request to establish a session; send, to a network repository function (NRF), a second request requesting discovery of a session management function (SMF), wherein the second request includes a cellular internet of things (CIoT) indication; receive, from the NRF, an identifier of the SMF that supports CIoT optimization; and send, to the SMF, a third request to establish the session for CIoT packet transmission.
 12. The AMF of claim 11, wherein the third request comprises: a data network name (DNN); a single network slice selection assistance information (S-NSSAI) associated with the session; an identifier of the session; a session type associated with the session; and an identifier of the wireless device.
 13. The AMF of claim 11, wherein the session is a packet data unit (PDU) session, and wherein the CIoT indication is a control plane CIoT optimization indication.
 14. The AMF of claim 11, wherein the CIoT indication is a CIoT optimization indication.
 15. The AMF of claim 11, wherein the first request comprises the CIoT indication.
 16. The AMF of claim 15, wherein the SMF supports exchange of user data of the wireless device between the wireless device and the SMF using a non-access stratum message, and wherein the exchange of the user data comprises transmission of the user data over a control plane.
 17. The AMF of claim 11, wherein the instructions, when executed by the one or more processors, further cause the AMF to send, to a network slice selection function (NSSF), a slice selection request indicating that a slice is for the session.
 18. The AMF of claim 17, wherein the instructions, when executed by the one or more processors, further cause the AMF to receive, from the NSSF, an address of the NRF.
 19. The AMF of claim 11, wherein the first request comprises an identifier of the session.
 20. A system, comprising: a wireless device; a network repository function (NRF); a session management function (SMF); and an access and mobility management function (AMF) comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors of the AMF, cause the AMF to: receive, from the wireless device, a first request to establish a session; send, to the NRF, a second request requesting discovery of a session management function (SMF), wherein the second request includes a control plane cellular internet of things (CIoT) indication; receive, from the NRF, an identifier of the SMF; and send, to the SMF, a third request to establish the session for CIoT packet transmission. 